edicine 9 (2008) 184–187

Case Report

Cardiovascular Revascularization M

Thrombolysis in acute nonmassive pulmonary embolism: potential role ofmultidetector-row spiral computed tomography in decision making

Gaetano Nuciforaa,⁎, Piero Pellegrinib, Fjoralba Hyskoc,Raheleh Rashidia, Diran M. Igidbashiana

aCardiology Unit, Gorizia Hospital, Gorizia, ItalybRadiology Unit, Gorizia Hospital, Gorizia, Italy

cRadiological Science Department, Azienda Ospedaliero-Universitaria di Udine, Udine, Italy

Received 10 August 2007; accepted 20 August 2007

Abstract In the setting of suspected or confirmed nonmassive pulmonary embolism (PE), transthoracic

⁎ Corresponding aVeneto, 171. 34170,0481592456.

E-mail address: gn

1553-8389/08/$ – seedoi:10.1016/j.carrev.2

echocardiography (TTE) is an important tool to identify patients who could benefit fromthrombolytic therapy, because of right ventricle (RV) dysfunction, and to monitor the dynamicresponse of the RV to reperfusion therapy. Unfortunately, certain patient characteristics such asobesity, lung disease, postsurgical state, or respiratory distress often lead to inadequateultrasonographic imaging quality. In such patients, multidetector-row spiral computed tomography(MSCT) may become even more important. We present a female obese patient with acutenonmassive PE in whom TTE did not allow a reliable evaluation of the RV. Conversely, MSCT,beyond a direct demonstration of intravascular thrombi, detected multiple signs suggesting RVdysfunction. According to these findings, thrombolysis was safely performed, obtaining a rapidclinical improvement and a regression of RV dysfunction.© 2008 Elsevier Inc. All rights reserved.

Keywords: Nonmassive pulmonary embolism; Transthoracic echocardiography; Multidetector-row spiral computed

tomography; Right ventricle dysfunction

1. Introduction

We report a female obese patient with acute nonmassivepulmonary embolism (PE) in whom transthoracic echocar-diography (TTE) did not allow a reliable evaluation of rightventricle (RV) function. Conversely, contrast-enhancedmultidetector-row spiral computed tomography (MSCT),beyond a direct demonstration of multiple filling defects inthe pulmonary arteries, revealed a markedly dilated RV, with

uthor. Cardiology Unit, Gorizia Hospital, Via VittorioGorizia, Italy. Tel.: +39 0481592033; fax: +39

ucifora@cardionet.it (G. Nucifora).

front matter © 2008 Elsevier Inc. All rights reserved.007.08.003

interventricular septum flattening. Because of the evidenceof RV dysfunction at MSCT, thrombolytic therapy wasperformed, with rapid improvement of her respiratory status.Follow-up MSCT study 10 days later revealed a reduction offilling defects and an improved RV function.

2. Case description

A previously healthy 56-year-old obese woman (weight,120 kg; height, 1.70 m) presented to the emergencydepartment because of sudden-onset dyspnea and chestpain. At physical examination, she was tachycardic (heartrate, 130 beats/min) and tachypneic (respiratory rate,30 breaths/min); her blood pressure was 110/70 mmHg,and her room air oxygen saturation was 92%. Cardiac

Fig. 1. (A and B) Contrast-enhanced MSCT at admission shows large filling defects (white arrows) at the bifurcation and at the segmental level of both right andleft pulmonary arteries. Furthermore, dilatation of the main pulmonary artery (maximum diameter, 3.4 cm), superior vena cava (maximum diameter, 3.1 cm),and azygos vein (maximum diameter, 1.9 cm) is present. (C and D) Ten days after thrombolytic therapy, intravascular filling defects are reduced (white arrows),and the main pulmonary artery (maximum diameter, 2.4 cm), superior vena cava (maximum diameter, 2.0 cm), and azygos vein (maximum diameter, 1.2 cm) areless dilated. *Azygos vein; PA, pulmonary artery; SVC, superior vena cava.

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examination was unremarkable. Her right leg appearedswollen, tender, and painful but well perfused.

A 12-lead electrocardiogram showed sinus tachycardia andminimal, diffuse, nonspecific, ST-segment depression. Thefirst cardiac troponin T determination was within normallimits, while plasmaD-dimerwasmarkedly elevated (1000 ng/ml; normal value b500 ng/ml) and blood gas analysis showedslight respiratory alkalosis (pH 7.47; pCO2 33.9 mmHg; pO2

75.0 mmHg). The chest X-ray was unremarkable.Due to clinical suspicion of PE, a contrast-enhanced

16-slice spiral CT (Somatom Sensation 16, Siemens MedicalSolutions) was performed, revealing filling defects at thebifurcation and at the segmental level of both right and leftpulmonary arteries (Fig. 1A and B). The MSCT examallowed also an evaluation of RV function; the RV wasmarkedly dilated with an increased RV/LV ratio andinterventricular septum flattening (Fig. 2A). Furthermore,the main pulmonary artery, superior vena cava, and azygosvein were dilated (Fig. 1A and B). Limb venous ultrasono-graphy was also performed, revealing thrombosis of the rightpopliteal vein.

A TTE was also performed, but the patient wastechnically very difficult to image due to obesity; the leftventricle (LV) appeared hyperkinetic, while a reliableevaluation of RV function was not feasible.

Because of evidence of RV dysfunction on MSCT,thrombolysis with tenecteplase (10,000 U bolus) deliveredthrough a peripheral vein was performed and unfractionatedheparin (5000 U bolus followed by infusion at 1000 U/h)was administered. The patient reported a marked sympto-matic improvement over the next hour, and the followingcourse was uneventful. A follow-up MSCTstudy of the chestwas performed 10 days later, revealing a reduction of fillingdefects in the pulmonary arteries (Fig. 1C and D) and a lessdilated RV, with resolution of the interventricular septumdisplacement (Fig. 2B).

3. Discussion

In the setting of suspected or confirmed nonmassive PE,TTE is an important tool to identify patients who could

Fig. 2. (A) Contrast-enhanced MSCT at admission shows marked dilatationof the RV (maximum minor axis diameter, 5.75 cm; RV/LV diameter ratio,2.0) and interventricular septum flattening. (B) Ten days after thrombolytictherapy, contrast-enhanced MSCT shows regression of the RV dilatation(maximum minor axis diameter, 3.8 cm; RV/LV diameter ratio, 0.9) andresolution of the interventricular septum displacement. LA, left atrium; RA,right atrium.

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benefit from thrombolytic therapy, because of RV dysfunc-tion, and to monitor the dynamic response of the RV toreperfusion therapy [1,2]. The most important echocardio-graphic indirect signs of right pressure overload are RVenlargement, which can be associated with RV hypokinesis;interventricular septum flattening or bulging toward the LVin diastole; decreased LV volume (“empty LV” appearance);inferior vena cava dilatation, often without inspiratorycollapse; tricuspid valve insufficiency with pulmonaryhypertension; and pulmonary artery dilatation [2].

Echocardiographic study of RV function, however, hassignificant limitations due to the chamber shape, whichpoorly approximates to any convenient geometric model;chamber orientation and location behind the sternum; andpoor definition of the endocardial boundary because of avariable trabeculation pattern [3]. TTE is also an operator-dependent modality, and certain patient characteristics suchas obesity (as in our case), lung disease, postsurgical state, orrespiratory distress often lead to inadequate image quality.

In such patients with limited ultrasonographic imagingquality, MSCT may become even more important, providingimportant diagnostic and prognostic information.

MSCT is indeed becoming the new standard of referencefor imaging nonmassive PE; due to its better spatialresolution, MSCT allows visualization of peripheral pul-monary arteries and detection of small emboli in comparisonto spiral CT angiography [4–6]. A quantitative measure ofthe amount of clot burden within the pulmonary vasculatureis also feasible, according to the anatomic subdivisionsinvolved; this quantitative CT index of vasculature obstruc-tion is a sign of hemodynamic severity of PE and may berelevant for patient treatment [7,8].

Beyond a direct demonstration of intravascular thrombi,modern MSCT scanners may also detect other useful signssuggesting the hemodynamic severity of PE. Dilatation ofthe main pulmonary artery is an index of increasedpulmonary artery pressure [9], and increased diameters ofthe azygos vein and superior vena cava correlate withincreased right atrial pressure [8,10].

Furthermore, contrast opacification of the heart during astandard chest MSCT protocol for PE allows evaluation ofcardiac anatomy, qualitative assessment of the cardiacchambers and the interventricular septum, and measurementof ventricular dimensions [8–18]. RV dysfunction onMSCT (defined by the presence of RV dilatation andinterventricular septum flattening or shift toward the LV)correlates with RV dysfunction on echocardiography and isemerging as an important marker for predicting subsequentadmission to the intensive care unit [12], adverse clinicalevents [13], and early death [14] in patients with acute PE.Particularly, an increased RV/LV diameter ratio (defined as≥1) was found to correlate with the extent of the clot in thepulmonary circulation and to discriminate survivors fromnonsurvivors [10].

At CT examination, our patient showed multiple signs ofhemodynamic severity of PE (large clot burden within thepulmonary vasculature; dilatation of the main pulmonaryartery, superior vena cava, and azygos vein; dilatation of theRV with interventricular septum flattening), while TTE wasunable to provide useful diagnostic and prognostic clues dueto inadequate image quality. According to the CT findings,thrombolysis was performed with tenecteplase, recentlyproposed as a safe and effective drug for the treatment ofacute massive and nonmassive PE [19]. The patient'srespiratory status indeed rapidly improved, without reportingadverse side effects; furthermore, RV dysfunction regressedand intravascular filling defects reduced, as shown by afollow-up MSCT study performed 10 days later.

In conclusion, MSCT often provides the only opportunityto evaluate RV function among patients with acutenonmassive PE and inadequate image quality at TTE; insuch cases, if signs of right pressure overload are present onMSCT, in the absence of contraindications, thrombolysiscould be safely performed. Repeating an MSCT study in thefollowing days is useful to evaluate not only residual clot

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burden but also the RV response to reperfusion therapy,potentially identifying patients at risk for developing chronicthromboembolic pulmonary hypertension [17].

4. Summary

We present a female obese patient with acute nonmassivePE in whom TTE did not allow a reliable evaluation of theRV. Conversely, MSCT, beyond a direct demonstration ofintravascular thrombi, detected multiple signs suggesting RVdysfunction. According to these findings, thrombolysis wassafely performed, obtaining a rapid clinical improvement anda regression of RV dysfunction.

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