Elsevier

Academic Radiology

Volume 24, Issue 7, July 2017, Pages 860-866
Academic Radiology

Original Investigation
Cardiovascular Computed Tomography Findings after Pneumonectomy: Comparison to Lobectomy

https://doi.org/10.1016/j.acra.2017.01.020Get rights and content

Rationale and Objectives

To identify and compare cardiovascular findings on computed tomography (CT) scans after pneumonectomy (PNX) with those after lobectomy (LOBX).

Materials and Methods

Pre- and postoperative CT scans from 25 PNX patients were retrospectively analyzed and compared to those from 30 LOBX patients. The diameter of the main pulmonary artery (PA) and its ratio to the ascending aorta (PA/Ao) were determined. Cardiac morphometry values were ascertained by measuring maximum diameters of the right and left ventricle on axial (RVaxial, LVaxial) and four-chamber (RV4-ch, LV4-ch) views. RVaxial/LVaxial and RV4-ch/LV4-ch ratios were calculated. Vessel stumps were evaluated for thrombosis.

Results

After PNX, PA (31.1 ± 5.8 mm vs 28.7 ± 5.4 mm, P = 0.003), PA/Ao (0.97 ± 0.15 vs 0.86 ± 0.12, P = 0.0001), and cardiac morphometry values significantly increased (RVaxial 43.6 ± 7.4 vs 39.4 ± 7.1, P = 0.029; RV4-ch 41.1 ± 6.3 vs 37.6 ± 5.7, P = 0.041; RVaxial/LVaxial 1.18 ± 0.27 vs 1.03 ± 0.22, P = 0.04; RV4-ch/LV4-ch 1.17 ± 0.21 vs 1.02 ± 0.16, P = 0.03). There were no significant differences between right and left PNX. One case of PA stump thrombosis was identified after right PNX. LOBX resulted in a significant increase in PA (30.6 ± 4.3 vs 28.7 ± 3.5, P = 0.005) and PA/Ao (0.90 ± 0.09 vs 0.85 ± 0.10, P = 0.017), whereas cardiac morphometry values were not significantly changed compared to baseline values. No vessel stump thrombosis was observed after LOBX. In comparison to LOBX, all ascertained values were significantly elevated after PNX.

Conclusions

Morphologic alterations of the cardiovascular system following PNX can be identified on CT scans. Alterations are more distinct after PNX compared to LOBX.

Introduction

Pneumonectomy (PNX) has various early and late effects on the cardiovascular system that are based on displacement of the heart and major vessels 1, 2, altered hemodynamics in vessel stumps 3, 4, increased perfusion to the remaining lung tissue (5), and elevated vascular resistance 6, 7. In about 40% of patients after PNX these effects were shown to induce pulmonary hypertension (PH), that is, resting mean pulmonary artery pressures (PAP) exceeding 25 mmHg with concomitant dysfunction and remodeling of the right ventricle 8, 9.

Doppler echocardiography was found to be useful in the evaluation of patients undergoing PNX as the right ventricular function and morphology as well as PAP can be assessed noninvasively 1, 5, 10.

As a result of PNX, early modifications demonstrated by echocardiography include a progressive increase in systolic PAP that starts at the end of the first week after surgery, inducing a dilation of the right ventricle that becomes significant 6 months postoperatively 1, 5, 9, 10. Reported values for mean systolic PAP range from 27.3 ± 9.3 mmHg to 40.5 ± 12.5 mmHg 6 months after PNX 1, 5, 9 and 33.4 ± 7.9 mmHg to 34.1 ± 14 mmHg 1, 9 1 year following PNX, respectively. Furthermore, patients with systolic PAP exceeding 35.5 mmHg 1 year postoperatively were shown to be at higher risk of a suboptimal clinical outcome (9).

However, computed tomography (CT) studies addressing alterations of the cardiovascular system after PNX are missing. Therefore, the purpose of the present study was (1) to retrospectively evaluate chest CT scans from PNX patients for morphologic modifications of the heart and main pulmonary vessels and (2) to identify measurements that may be valuable for further prospective evaluation as clinical outcome indicators. These would be useful as CT scans are routinely performed in patients after PNX, especially in those after surgery for malignancy.

Because echocardiographic findings were shown to be dependent upon the amount of resected pulmonary vascular bed 1, 5, we further aimed to compare our results to CT findings of patients who underwent lobectomy (LOBX).

Section snippets

Data Analysis

Data from PNX and LOBX patients were collected retrospectively between 2006 and 2014. The need for informed consent was waived by the local ethics committee. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Indications for PNX and LOBX are listed in Table 1. Inclusion criteria were the following: contrast-enhanced CT before and after PNX or typical LOBX, absence of heart failure, absence of severe emphysema, and lung

PNX

The first follow-up CT scan was performed after a median of 13 weeks (range 3–34 weeks) after surgery. Morphometric data of PNX patients are summarized in Table 2. Main PA diameter and its ratio to the ascending aorta (PA/Ao) significantly increased. Cardiac morphometry revealed significantly increased diameter of the RV and its ratio to the LV diameter on both axial sections and reconstructed four-chamber views. Postoperative changes seen before and after the median follow-up time of 13 weeks

Discussion

Our data show that PNX and LOBX impact pulmonary artery dimensions on CT scans.

Moreover, PNX but not LOBX may have the potential to induce right heart remodeling.

On CT scans, the axial diameter of the main PA was repeatedly shown to be a predictor of increased PAP and PH with a sensitivity and specificity ranging up to 87% and 100%, respectively 15, 16, 17, 18. The PA/Ao ratio was demonstrated as a more reliable marker of increased PAP and PH, especially in patients with fibrotic lung disease

References (34)

  • A.G. Bach et al.

    CT pulmonary angiography findings that predict 30-day mortality in patients with acute pulmonary embolism

    Eur J Radiol

    (2015)
  • F. Venuta et al.

    Long-term Doppler echocardiographic evaluation of the right heart after major lung resections

    Eur J Cardiothorac Surg

    (2007)
  • ShenK.R. et al.

    Postpneumonectomy syndrome: surgical management and long-term results

    J Thorac Cardiovasc Surg

    (2008)
  • S.Y. Kim et al.

    Filling defect in a pulmonary arterial stump on CT after pneumonectomy: radiologic and clinical significance

    AJR Am J Roentgenol

    (2005)
  • K. Ohtaka et al.

    Left upper lobectomy can be a risk factor for thrombosis in the pulmonary vein stump

    J Cardiothorac Surg

    (2014)
  • C.N. Foroulis et al.

    Study on the late effect of pneumonectomy on right heart pressures using Doppler echocardiography

    Eur J Cardiothorac Surg

    (2004)
  • R.J. Kalathiya et al.

    Pneumonectomy for non-small cell lung cancer: outcomes analysis

    South Med J

    (2012)

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