Br Heart J 1990;63:253-9

TECHNOLOGY

Short term results of percutaneous transluminalcoronary angioplasty with the monorail technique:experience in the first 1000 patients

Pim J de Feyter, Patrick W Serruys, Marcel van den Brand, Harry Suryapranata,Kevin Beatt

CatheterisationLaboratory,Thoraxcenter,Erasmus University,Rotterdam, TheNetherlandsP J de FeyterP W SerruysM van den BrandH SuryapranataK BeattCorrespondence toDr Pim J de Feyter,Catheterisation Laboratory,Thoraxcenter, ErasmusUniversity, PO Box 1738,3000 DR Rotterdam, TheNetherlands.

Accepted for publication12 December 1989

AbstractThe monorail technique allowsmonitoring of all steps of the coronaryangioplasty procedure by high qualitycoronary angiography; easy, rapid, andsafe recrossing and redilatation of thelesion if necessary; and stepwise dilata-tion of a stenosis with sequential increaseof size of balloons. Transstenotic pres-sure differences cannot, however, bemeasured through the narrow shaft ofthe standard monorail balloon catheter.The monorail technique was used in

1014 patients (820 men, 194 women; meanage 57 8 years (range 24 to 84)). Theindication for coronary angioplasty wasstable angina in 52%, unstable angina in40%, and acute myocardial infarction in8%. Single vessel coronary angioplastywas attempted in 78%, multilesioncoronary angioplasty in 11%, andmultivessel coronary angioplasty in 11%.Angiographic success (reduction of sten-osis to less than 50% of the luminaldiameter) of all attempted lesions wasachieved in 93%. The technique wasclinically successful-that is, angio-graphic success of all attempted lesions,no occurrence of a major complication(death, myocardial infarction, acutebypass surgery), and improvement ofsymptoms-in 92% and partially suc-cessful in 1-3%. The clinical success rateswere similar for stable angina (91%) andunstable angina (94%), but were some-what lower for acute myocardial infarc-tion (88%). Failure without major com-plication occurred in 3-4% of thepatients. Failure with a major complica-tion occurred in 3-3% (death 0-3%,myocardial infarction 2-4%, and acutebypass surgery 2-3%). The total majorcomplication rate was higher in unstableangina (4-2%) than in stable angina(3-0%).These results indicate that the mono-

rail technique can be applied safely andeffectively for coronary angioplasty ofpatients with stable angina, unstableangina, and acute myocardial infarction.

Significant advances have been made in thetechnology of guiding catheters, dilatation

catheters, and guide wires since the firstintroduction of percutaneous transluminalcoronary angioplasty in 1977 by AndreasGruentzig.' Simpson et al further developedthe balloon dilatation equipment by intro-ducing a steerable coaxial guide wire.2 Sub-sequent improvements were the miniaturisa-tion of the balloon catheters (low profileballoons) to facilitate the crossing of verysevere and distal stenoses. A more recentimprovement is the combination of the long(exchange) guide wire technique34 and anewly developed balloon catheter to form onenew dilatation system: the monorail system,for which a change in dilatation technique isneeded.5 This monorail technique allows allsteps of the coronary angioplasty procedure tobe monitored on high quality angiograms:easy, rapid, and safe recrossing and redilata-tion of the stenosis if necessary; stepwisedilatation of a stenosis with sequential use ofbigger balloons.We describe our experience and the short

term results of coronary angioplasty with themonorail technique in the first 1000 patients.

Patients and methodsPATIENTSFrom June 1986 to December 1988 1472patients underwent coronary angioplasty atthe Thoraxcenter in Rotterdam. We excluded(a) patients in whom a stent was implanted(n = 13), (b) patients who were selected forthe assessment of a newly developed catheterballoon system (n = 46); and (c) patients withbifurcation lesions in whom the (partial) kiss-ing balloon technique was used (n = 15).Table 1 shows the baseline clinical character-istics of the remaining 1398 patients. Thesepatients were classified into three groups:1014 patients were selected for coronaryangioplasty with the monorail technique, 325patients were selected for coronary angio-plasty with the long guide wire technique, and59 patients were selected for coronary angio-plasty with other balloon catheters(microbore, 54 patients; balloon on wire, fivepatients).

ANGIOGRAPHYCoronary artery lesions were classified asoccurring in the left anterior descending

253 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from

de Feyter, Serruys, van den Brand, Suryapranata, Beatt

Table I Baseline clinictaccording to type of coron

Mean age (range) (yr)> 70 yrFemalesOld MIPrevious CABGEF< 45% (%)

Multivessel disease:2 vessel3 vessel

Total occlusion

Stable anginaUnstable anginaAcute MI

Attempt per vessel:LADRCACX

Bypass graftLeft main stem

Attempts per patient:Single vesselMultilesionMultivessel

*Attempted coronary adilatation technique and otMI, myocardial infarctio.grafting; EF, ejection fracartery; RCA, right coronaartery, n =number of patie

artery, left circumflary artery, wheth4within the artery itthat artery. There i

lesions of bypass lstem. Coronary stcpercentage of thelesion of > 50%dynamically imporwas defined as a

narrowing of moremajor coronary arsidered to be toanterograde flowangiography immetted coronary angiotion was calculattriculogram in theprojection.

HISTORYUnstable angina wI

rest associated wit]the ST segment oisigns of myocardialin cardiac enzymesor no developmenPatients were cocoronary angioplastacute myocardial inchest pain not reli4and ST segment eliat least two contigihours after the onse

al characteristics ofpatients CORONARY ANGIOPLASTY PROCEDUREary angioplasty attempted Intravenous heparin (100 mg) and aspirin (250

Longguide mg) were given at the start of the procedure.Monorail wire Other The electrocardiogram and blood pressuretechniqwu technique technique* were monitored continuously. To prevent(n= 1014) (n=325) (n=59)% (n) % (n) % (n) coronary spasm intracoronary isosorbide58(24-85) 57(32-82) 56(35-78) dinitrate (10 to 30 /ig) was injected and this was11(108) 12(39) 15 (9) repeated when necessary. The initial pressure19(194) 16(53) 22(13) of balloon inflation was 2-0 atms, with sub-10 (97) 14 (47) 314 (19) sequent inflations of up to 12 atms. The5(47) 5(16) 7(4) duration of inflation was adjusted for electro-

cardiographic changes, the drop in blood19(193) 23(74) 25(15) pressure, or induced pain. The number of8 (75) 14 (47) 27 (16) balloon inflations varied according to the

52 (523) 70 (227) (47) appearance of the lesion on angiography40 (407) 26 (85) 20 (12) immediately after dilatation.8 (84) 4(13) 0 (0) Multivessel dilatation was defined as dilata-

tion ofone or more lesions in two or more major51(578) 43 (159) 43 (32) epicardial coronary arteries. Multilesion20 (221) 25 (92) 23 (18) dilatation was defined as dilatation of two or3 (36) 5 (17) 1 (1) more lesions in one major epicardial coronary1(5) 1(2) 0 (0) artery. In patients with stable angina and

78 (791) 75 (244) 66 (39) multivessel angioplasty, dilatation of the most11(114) 11(36) 20(12) severe narrowing in the vessel supplying the11(109) 14(45) 14(8) largest amount of jeopardised myocardium

ngioplasty with other standard (critical stenosis) was always attempted firstther balloons. and, if successful, additional vessel(s) weren; CABG, coronary artery bypiass dilated. Angioplasty of a second or third vesselnton; LAD, left antericjr descednry artery; CX, circumflex coronary was not attempted if the attempted dilatation ofnits, the critical lesion was unsuccessful or when

angiographic success was equivocal or if theresult was consistent with a dissection thatmight progress to total occlusion. When avessel with high grade disease suppliedcollaterals to another vessel, the vessel

[ex artery, and right coron- receiving the collateral supply was dilated firster or not they occurred to protect collateral flow. When sequentialtself or in a side branch of lesions were present in one vessel, the morewas a separate category for proximal lesion was dilated first. In patientsgrafts or of the left main with unstable angina and multivessel diseaseenosis was expressed as a only the critical lesion (determined by theluminal diameter and a electrocardiographic changes and angiographicwas regarded as haemo- appearance-that is, the severity and complex-rtant. Multivessel disease ity of the lesion, irregular borders, intra-luminal arterial diameter coronary thrombus) was dilated except in 37than 50% in at least two patients who were judged to have more than

teries. A vessel was con- one severe lesion. These were dilated in thetally occluded when no same session. In patients with acute myocardialof dye was visible at infarction only the infarct related lesion wasdiately before the attemp- dilated.plasty. The ejection frac- The success of the procedure was judged byted from the left ven- both angiographic and clinical criteria.300 right anterior oblique Angiographic success was defined as a reduc-

tion ofthe luminal diameter stenosis to < 50%.A complete clinical success was defined asangiographic success in all attempted lesions,associated with an improvement of symptoms

as defined as chest pain at and without evidence of myocardial infarctionh documented changes in or the requirement for coronary artery bypassr T wave and no obvious surgery during hospital stay. An incompleteI cell necrosis (an increase clinical success was defined as angiographicof less than twice normal success with the critical lesion but failure

t of abnormal Q waves). with additional lesion(s), associated withinsidered for immediate an improvement of symptoms and withoutty if they had symptoms of evidence of myocardial infarction or need forLfarction (severe, prolonged coronary artery bypass surgery during hospitaleved by glyceryl trinitrate stay.evation of at least 1 mm in A coronary angioplasty was regarded as auous leads) for less than 6 failure if (a) the angiographer was unable tot of symptoms. reach, cross, or dilate the critical lesion while

254 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from

Coronary angioplasty with the monorail technique

Figure I The monorail balloon catheter consists of a lumen running the length of the catheter to inflate and deflate the balloon, and a second lumen(1) limited to the distal end of the catheter that acts as a "monorail" and is occupied by the guide wire.

attempting to perform a coronary angioplasty(failure without complications) or (b) thecoronary angioplasty procedure resulted indeath, myocardial infarction, or emergencycoronary artery bypass surgery. A peri-interventional (complication of angioplasty)myocardial infarction was defined as thedevelopment of an abnormal Q wave(> 0-03 mm) or a typical increase in cardiacenzymes. A perioperative (complication of abypass operation) myocardial infarction wasdefined as the development of an abnormal Qwave (> 0 03 mm). All procedures were carriedout with a surgical team on standby. After theprocedure the sheaths were left in place for 6-8hours and all patients were monitored for 24hours in an intermediate coronary care unit. Allpatients were treated with oral nifedipine 60mg daily for 24-36 hours after coronary angio-plasty and were discharged after 1 to 2 days.The patients were treated with aspirin 500 mgdaily for 6 months.

MONORAIL TECHNIQUEThe monorail balloon catheter (Bonzel-Schneider-Medintag) has a single lumen forballoon inflation and a second lumen limited tothe first few centimetres of the distal end of thecatheter. This second lumen is occupied by theguide wire that acts as a sliding rail (monorail)for the balloon catheter (fig 1). Table 2 showsthe technical details for different types ofmonorail balloon catheters. In the monorailtechnique the guide wire alone (Schneider-Medintag 175 cm, 0-0012-0-0014 inch; ACS175 cm, 0-0014 inch) is initially positionedacross the lesion. The small diameter guidewire does not obstruct injection of contrast;thus it allows good delineation of the coronaryanatomy and facilitates positioning of the wireacross the lesion (fig 2a and b).The distal lumen of the balloon catheter is

then threaded over the positioned guide wire(the proximal part guide wire is outside theguiding catheter) and the catheter is advancedthrough the guiding catheter, into the coronaryartery tree, and eventually across the lesion (fig1). Because the position of the guide wireoutside the patient is fixed most ofthe position-

Table 2 Technical details of different monorail dilatation catheters

MaximumBalloon Deflated recommendeddiameter balloon Shaft balloon(mm) profile (inch) diameter pressure (atm)

Monorail-Bonzel, PVC (super)-low profile 20-42 0-043-0061 3F 8-10Monorail Piccolino, PET material 1 5-425 0 028-0 040 3F 8-12Monorail-Bonzel Snake, with distal 3-0-4-2 0-058-0063 3-6F 8pressure measurement, PVC

All three catheters are of the Schneider-Shiley type.PCV, polyvinylchloride; PET, polyethylene.

ing and withdrawing of the balloon is perfor-med without the need for fluoroscopic controland to and fro motion of the wire in the distalcoronary vessel is prevented. The reducedshaft diameter of the balloon catheter meansthat the injection of contrast when the balloonis in the guiding catheter is not obstructed andthis improves the delineation of the coronaryanatomy (fig 2c and 3).

After the final dilatation of the lesion theballoon catheter is completely withdrawn out-side the guiding catheter while the guide wireremains in the distal vessel. The result ofdilatation can again be evaluated under highquality angiographic control and, when neces-sary, the lesion can be easily recrossed andredilated (fig 2d).

OTHER CORONARY ANGIOPLASTY TECHNIQUESIn the remaining patients in whom the mono-rail technique was not used, coronary angio-plasty was performed by standard techniqueswith either fixed tip or steerable cathetersystems or by the long guide wire technique.3

CLASSIFICATION OF PATIENTSMonorail groupPatients were classified as being in the monorailgroup ifthe monorail technique was selected asthe first choice of catheter balloon system to beused. The patients always remained in themonorail group if, after failure with the mono-rail technique, an attempt with another ballooncatheter system was successful or unsuccessful.

Long guide wire group and other technique groupPatients were classified as being in the longguide wire group or other technique group ifeither technique was selected as the firstapproach. The patients remained in this groupeven after crossover to another technique.

ResultsMost of the baseline clinical characteristicswere similar in the three groups (table 1).However, attempted coronary angioplasty of atotal occluded lesion and multilesion dilatationwere more common in the long guide wire andthe other technique groups.Table 3 shows the short term results of

coronary angioplasty with the different tech-niques. The overall clinical and angiographicsuccess rate was lower in the groups classifiedas long guide wire technique and in particularin those classified as the other technique groupbut this may have been because more totalocclusions were attempted. The differences inoutcome therefore are a reflection of patientselection and do not indicate that one techniquewas better than the other.Table 4 shows the results of attempts with

%I 11 .I

=====.- ===I%I 01% 1%

255 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from

256 de Feyter, Serruys, van den Brand, Suryapranata, Beatt

s; .} 6 - °. J . .o .. ^:} o . :jS

.. : .: !:: ... S :.::

::_ o y .. , O : .;\' .: oo,v_,,t, __b,|,_ _ _w__ ....... __ _ S _ d ^._ S _ _ . - _ . 9 S 9 _ S _ . ... -......... .... _. _ __ _ _ .F Z.::,; i _

.-Six'lal E E\, ..... s¢¢.3N N _ss!;5

. ><m M!yM !;; .... o W _ a 0 4 g

S.* . . :'0:....* . ;. ,; ,. . . >; . .;: . : 5 :.:?...... . , . .; , : !!. :.!. 6 j: . . . S! S !. - i o .

.Q : :{ :.: :. :. :,. o ' O .0 ::OS : . . 9 6. ! :. . S : .;.SO !:: ;!: s o

.. o* : .. : ..... :. . . . .. .: iC : o. : :.: p : . . . ' ' S!: . ..:.:< ... a s,* .. < .. . o .:o . . o .: :: . .. e . : ;..: O . .:

.s

Oyg;o o: a:: o \. o :. ,!s __.. : ! . ' ' '7-

.: .: !! :_; y-_

.; s

Figure 2 (a) Guide wire alone positioned distal in the left anteriordescending artery. (b) Coronary anatomy is well displayed with theguide wire positioned in the artery. (c) Guide wire and deflated balloonpositioned at the lesion. (d) Satisfactory display of coronary anatomywith deflated balloon crossing the stenosis. (e) High quality angiogramobtained after withdrawal of balloon catheter, with guide wireremaining in the distal vessel.

Guidingcatheter8F

Figure 3 Comparison ofspace available within 8Fguiding catheter when aconventional dilatationcatheter (1 1 mm2) or amonorail balloon catheter(2 mm') is used. Guide

wire

on June 27, 2020 by guest. Protected by copyright.

http://heart.bmj.com

/B

r Heart J: first published as 10.1136/hrt.63.4.253 on 1 A

pril 1990. Dow

nloaded from

Coronary angioplasty with the monorail technique

Table 3 Short term results of coronary angioplasty with the monorail technique, thelong guide wire technique, and other technique

Long guideMonorail wire Othertechnique technique technique(1014) (325) (59)

Clinical success (%) (nos of patients)Complete 92(933) 87 (282) 66(39)Partial 1-3 (14) 2-5 (8) 8-5 (5)

Total of attempted lesions (no) 1240 407 79Angiographic success all lesions (%)* 93 (1154) 88 (359) 73 (58)Total of attempted total occlusions 75 47 16Angiographic success total 60 (45) 49 (23) 25 (4)

occlusions (%)*Angiographic success (total occlusions 95 (1109) 93 (336) 86 (54)

excluded) (%)

Failure without complication (%)t:Total 3-4 (34) 6-0 (20) 22 (13)Inability to cross with wire 1-8 (18) 4-5 (14) 20 (12)Inability to cross with balloon 0-4 (4) 1-0 (4) 2 (1)Inability to dilate 1-2 (12) 0-5 (2) 0 (0)

Failure with major complication (%)t:Total 3-3 (33) 4-5 (15) 3-5 (3)Death 0-3 (3) 0-6 (2) 0 (1)Myocardial infarction 2-4 (24) 2-8 (9) 3-5 (2)Acute bypass surgery 2-3 (23) 3-4 (11) 2 (1)

Other complications (%)t:Clot on wire 1-4 (14) 2 (7) 2 (1)Spasm 1-2 (12) 1-8 (6) 2 (1)Ventricular fibrillation 0-7 (7) 0-6 (2) 0 (0)Side branch occlusion 0-8 (8) 0-6 (2) 0 (0)

*Number of lesions is given in parentheses.tNumber of patients is given in parentheses.

another technique or balloon catheter afterinitial failure with the monorail technique.Tables 5, 6, and 7 show the short term results ofpercutaneous transluminal coronary angio-plasty with use of the monorail technique inpatients with stable angina, unstable angina,

Table 4 Short term results of attempts with anotherballoon dilatation catheter after initialfailure with themonorail technique

Attempt with other balloon catheterAttemptedlesions Total (n) Success (n) Failure (n)

Single lesion 5 1 (0) 4 (2)Multilesion/multivessel:

Culprit lesion 3 3 (1) 0 (0)Additional lesion(s) 8 7 (2) 1 (1)

Numbers in parentheses are patients with total occlusion.

and acute myocardial infarction. These resultsindicate that the monorail technique can beused as an elective (table 5), semi-elective (table6), or emergency procedure (table 7) andindicate that with the use of the monorailtechnique stenoses in all three major coronary

arteries and venous bypass grafts are equallyaccessible and that the primary success ratesand reasons for failure in these vessels are

comparable. Table 8 shows the short termresults of attempted coronary angioplasty withthe monorail technique for totally occludedlesions. The higher success rate in patients withunstable angina reflects the shorter intervalbetween total occlusion and attempted coron-

ary angioplasty.

DiscussionPrimary success of percutaneous transluminalcoronary angioplasty depends on many factors.The most important are patient selection,lesion location, operator experience, dilatationequipment, and adequate radiographic equip-ment.' Undoubtedly improvements inballoon catheter designs and dilatationtechniques have increased success rates. Wedescribe the initial results obtained with the useof the monorail technique and do not comparethe success rates or complication rates with themonorail technique with other techniques or

other balloon catheter systems. Although sucha study is desirable, it would require a ran-

domised design and, because of the expectedsmall differences in outcome, it would requirethe recruitment of a large study group frommore than one centre with many investigators.Furthermore, such a study would take severalyears and continuing refinements andimprovements of balloon catheters or theintroduction ofnew techniques (laser, atherec-tomy, abrasive catheters, ultrasound energy)would make the comparison unreliable. Wedescribe our experience with the monorailtechnique used as a primary routine in one

interventional cardiology centre in which about

Table 5 Short term results ofpercutaneous transluminal coronary angioplasty by the monorail technique in patientswith stable angina

Failure*Clinical success

No complications With complicationsAngiographic

Total success Compkte Partial UC UB Total Death MI CABG(n) % (lesions) % (n) % (n) % (n) % (n) % (n) (n) (n) (n)

Single vessel attempt:LAD 202 92 (186) 92 (186) - 2-5 (5) 1-5 (3) 4 0 (8) 0 4 8RCA 99 87 (86) 87(86) - 6(6) 2(2) 5(5) 0 3 2CX 70 94 (66) 94 (66) - 3 (2) 1-5 (1) 1-5 (1) 0 1 1Bypass graft 9 89 (8) 89 (8) - 11(1) 0 0 0 0 0Left mainstem 4 100 (4) 100 (4) - 0 0 0 0 0 0

Multilesion attempt:LAD 41 96 (80) 95 (39) 2-5 (1) 0 0 2-5 (1) 0 1 1RCA 22 98 (42) 95 (21) 5 (1) 0 0 0 0 0 0CX 4 88 (7) 75 (3) 25 (1) 0 0 0 0 0 0

Multivessel attempt:LAD/CX 31 97 (58) 94 (29) 6 (2) 0 0 0 0 0LAD/RCA 23 93 (43) 91 (21) 4 (1) 0 0 4 (1) 0 1 0RCA/CX 12 75 (18) 58 (7) 33 (4) 8 (1) 0 0 0 0 0Bypass graft/other 4 100 (8) 100 (4) 0 (0) 0 0 0 0 0LAD/CX/RCA 2 83 (5) 50 (1) 50 (1) 0 0 0 0 0 0

Allattempts 523 92(611) 91(475) 2(11) 2-8(15) 1-2(6) 3-0(16) 0 10 12

*UC, uncrossed wire; UB, unable to cross lesion to dilate with balloon.MI, myocardial infarction; CABG, coronary artery bypass grafting; LAD, left anterior descending coronary artery; RCA, rightcoronary artery; CX, circumflex coronary artery. n= number of patients.

257 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from

de Feyter, Serruys, van den Brand, Suryapranata, Beant

Table 6 Short term results ofpercutaneous transluminal coronary angioplasty by the monorail technique in patientswith unstable angina

Failure*Clinical success

No complications With complicationsAngiographic

Total success Complete Partial UC UB Total Death MI CABG(n) % (lesions) % (n) % (n) % (n) % (n) % (n) (n) (n) (n)

Single vessel attempt:LAD 183 94(172) 94(172) - 1 (2) 0 5 (9) 2 7 6RCA 69 93(64) 93 (64) - 1-5 (1) 0 6 (4) 1 3 2CX 62 97 (60) 97 (60) - 0 0 3 (2) 0 2 2Bypass 9 100 (9) 100 (9) - 0 0 0 (0) 0 0 0

Multilesion attempt:LAD 26 94(50) 88(23) 4 (1) 0 0 8 (2) 0 2 1RCA 12 100 (24) 100(12) - 0 0 0 (0) 0 0 0CX 9 94(17) 89 (8) 11 (1) 0 0 0 (0) 0 0 0

Multivessel attempt:LAD/CX 13 96(25) 92(12) 8 (1) 0 0 0 0 0 0LAD/RCA 12 100(24) 100(12) - 0 0 0 0 0 0RCA/CX 8 100 (16) 100 (8) - 0 0 0 0 0 0L-main/CX 1 100 (2) 100 (1) - 0 0 0 0 0 0

Bypass/LAD(2) 3 100 (6) 100 (3) - 0 0 0 0 0 0CX(1)

All attempts 407 95 (469) 94(384) 0-7 (3) 0 7 (3) 0 4-2 (17) 3 14 11

n= number of patients.See footnote to table 5 for abbreviations.

Table 7 Acute results ofpercutaneous transluminalcoronary angioplasty by the monorail technique inpatients with acute myocardial infarction*

FailureClinicalsuccess UC UB

n (%) (n) % (n) % (n)

Single vessel:LAD 43 93 (40) 0 7(3)RCA 32 81(26) 0 19 (6)CX 8 88 (7) 0 12 (1)Bypass graft 1 100 (1) 0 0

All attempts 84 88 (74) 0 12 (10)

*There were no deaths.See footnote to table 5 for abbreviations.

500 patients per year were treated by angio-plasty.

MONORAIL TECHNIQUENowadays, in elective procedures with lowprofile or super low profile dilatation cathetersthe initial success rate should be well over

90%.0""2 None the less, angioplasty patientscontinue to be at risk of major periproceduralcomplications. Optimal visualisation andcontinued access to the distal part of the vesselare useful in preventing, recognising andfacilitating the management of these acutecomplications.The monorail technique allows (a) optimal

visualisation to monitor all the important steps

of the coronary angioplasty procedure; (b) safe,rapid, and easy recrossing of the lesion ifnecessary, and (c) initial crossing of a tight or

complex lesion with a small balloon andrecrossing of the stenosis with larger balloons.Optimal visualisation is essential for negotia-tion of the proximal and distal parts of thecoronary artery, for crossing of the lesion, andfor recognition and management of the com-plications of the procedure. If dilatation isincomplete or an acute coronary occlusionoccurs during angioplasty the monorail tech-nique enhances recognition of these situationsand allows easy and safe recrossing with thesame or a larger balloon. If this is unsuccessfula monorail coronary perfusion catheter can beintroduced and coronary blood perfusion can

be performed. The guide wire is withdrawnonly after the control angiogram has shown a

satisfactory result. In patients with a high riskof abrupt occlusion after an initial successfuldilatation the technique permits monitoring ofthe patient in the catheterisation laboratorywith continued access provided by the wire inthe distal part of the vessel.

LIMITATIONS OF THE MONORAIL TECHNIQUEThe shaft of the standard monorail ballooncatheter is too narrow to allow measurement ofthe transstenotic pressure difference. Un-doubtedly measurement of transstenoticpressure differences by commercial equipmentis less accurate than by high-fidelity micro-

Table 8 Short term results ofpercutaneous transluminal coronary angioplasty by the monorail technique in patientswith occlusion of a coronary artery

Failure

Clinical success No complications With complications

Complete Partial UC UB Total Death MI CABG(n) % (n) % (n) % (n) % (n) % (n) (n) (n) (n)

Stable angina 50 52 (26) 8 (4) 30 (15) 8 (4) 2 (1) 0 1 0Unstable angina 25 76 (19) 0 (0) 12 (3) 0 (0) 12 (3) 1 2 2

See footnote to table 5 for abbreviations.

258 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from

Coronary angioplasty with the monorail technique

manometers.3 14 None the less, haemodynamicevaluation of the lesion by such methods mayhelp to predict restenosis"5 and provideimmediate additional information to supportthe angiographic result. Reduction in thediameter of the catheter allows high qualityvisualisation but precludes measurement of thetransstenotic pressure gradient whereas an

increase in diameter allows measurement of a

pressure gradient but precludes high qualityangiography. We believe that high qualityvisualisation is more helpful than measurementof a transstenotic pressure drop in the assess-ment of the result immediately after dilatation.The Monorail-Bonzel Snake balloon catheter,however, is designed to measure the drop inpressure gradient (table 2).The poor pushability and occasional kinking

of the guide wire during retraction of theballoon with the first generation monorailcatheters caused some concern. Both problemshave been substantially improved by lengthen-ing of the second distal lumen, which accom-

modates the guide wire, from 5 cm to 9-17 cm(Monorail Snake, 9 cm; Picolino, 17 cm).The risk of thromboembolic complications

(1-4%) was higher because the guide wireremains in the coronary artery for longer. Fullanticoagulation must be maintained (a secondor third bolus infusion of heparin may beneeded during lengthy procedures) with on linemonitoring of anticoagulation.

CONCLUSIONWith the monorail technique it is easierto obtain good angiograms to monitor allimportant steps of the coronary angioplastyprocedure and safe, easy, and rapid recrossingis facilitated. The monorail technique wassuccessful in 90% of 1000 patients and the rateof major complications (death, myocardialinfarction, acute bypass surgery) was <4%.The transstenotic pressure difference cannotbe measured through standard monorail

balloon catheters. In future, however, smallerguide wires will be developed to allowmeasurement ofpressure through the monorailcatheter.

1 Gruentzig AR, Senning A, Siegenthaler WE. Nonoperativedilatation of coronary artery stenosis-percutaneous trans-luminal coronary angioplasty. N Engl J Med 1979;301:61-8.

2 Simpson JB, Baim DS, Robert EW, et al. A new cathetersystem for coronary angioplasty. Am J Cardiol 1982;49:1216-22.

3 Dervan JP, McKay RG, Baim DS. The use of an exchangeguide wire in coronary angioplasty. Cathet CardiovascDiagn 1985;11:207-12.

4 Kaltenbach M. The long guide wire technique-a newtechnique for steerable balloon catheter dilatation ofcoronary artery stenoses. Eur Heart J 1984;5:1004-9.

5 Bonzel T, Wollschlaeger H, Kasper W, Meinertz T, Just H.The sliding rail system (monorail): description of a newtechnique for intravascular instrumentation and itsapplication to coronary angioplasty. Z Kardiol1987;76:1 19-22.

6 Detre KM, Myler RK, Kelsey SF, Van Raden M, To T,Mitchell H. Baseline characteristics of patients in theNational Heart, Lung, and Blood Institute PercutaneousTransluminal Coronary Angioplasty Registry. Am J Car-diol 1984;53:7C-1 1C.

7 Kelsey SF, Mullin SM, Detre KM, et al. Effect of inves-tigator experience on percutaneous transluminal coronaryangioplasty. Am J Cardiol 1984;53:56C-64C.

8 Meier B, Gruentzig AR. Learning curve for percutaneoustransluminal coronary angioplasty: skill, technology orpatient selection. Am J Cardiol 1984;53:65C-8C.

9 Faxon DP, Kelsey SF, Ryan TJ, McCabe CH, Detre K.Determinants of successful percutaneous transluminalcoronary angioplasty: report from the National Heart,Lung, and Blood Institute Registry. Am Heart J 1984;108(suppl 1):1019-23.

10 Anderson HV, Roubin GS, Leimgruber PP, Douglas JS Jr,King SB Jr, Gruentzig AR. Primary angiographic successrates of percutaneous transluminal coronary angioplasty.Am J Cardiol 1985;56:712-7.

11 Detre K, Holubkov R, Kelsey S, et al. Percutaneoustransluminal coronary angioplasty in 1985-1986 and1977-1981. The National Heart, Lung, and Blood Ins-titute Registry. N Engl J Med 1988;318:265-70.

12 Tuzcu EM, Simpfendorfer C, Badhwar K, et al. Determin-ants of primary success in elective PTCA for significantnarrowing of a single major coronary artery. Am J Cardiol1988;62:873-5.

13 Wijns W, Serruys PW, van den Brand M, et al. Transsten-otic pressure gradients obtained during coronary angio-plasty are useful but artifactual measurements [Abstract].Circulation 1984;70(suppl II): 11-299.

14 Sigwart U, Grbic M, Goy JJ, Essinger J. High fidelitypressure gradients across coronary artery stenoses beforeand after transluminal angioplasty [Abstract]. J Am CollCardiol 1985;5:521.

15 Leimgruber PP, Roubin GS, Hollman J, et al. Restenosisafter successful coronary angioplasty in patients withsingle-vessel disease. Circulation 1986;73:710-7.

259 on June 27, 2020 by guest. P

rotected by copyright.http://heart.bm

j.com/

Br H

eart J: first published as 10.1136/hrt.63.4.253 on 1 April 1990. D

ownloaded from