Ann Thorac Surg 2007;83:1992
© 2007 The Society of Thoracic Surgeons
Original Articles: General Thoracic
Invited commentary
Hyun-Sung Lee, MD, PhD
Center for Lung Cancer, National Cancer Center, 809 Madu1-dong, Ilsandong-gu, Goyang, Gyeonggi, 411-769, Korea
(Email: thoracic{at}ncc.re.kr).
The authors have to be commended for their excellent clinical results and their complete follow-up of dynamic magnetic resonance images of more than 5 years after pneumonectomy to examine the effects of pneumonectomy on the structure and function of the heart. They concluded that cardiac function in long-term survivors after pneumonectomy is compromised, and this may be explained by the altered position of the heart [1].
Conclusions from cross-sectional comparisons between the younger control group and the pneumonectomy group seem overdrawn. From my perspective, cardiac function of long-term survivors after pneumonectomy seems well preserved and compensated at rest, despite alteration of the heart position.
We believe that changes in pulmonary artery pressure and pulmonary vascular resistance affect right ventricular afterload after pneumonectomy. Consequently the dimensions of the right ventricle (RV) may adapt to maintain cardiac output by the Frank-Starling mechanism. Although deterioration has been observed for 4 to 6 months after the operation, we often see respiratory symptoms improve during several years of postoperative follow-up. It is still unclear whether this symptomatic improvement is associated with an improvement of cardiopulmonary function or not. The RV is not pressure-overloaded, because the pulmonary vascular bed is compliant and adjusts to wide variations in blood flow without much change in pressure. Small studies report that cardiac function after pulmonary resection is little affected at rest, but deteriorated with exercise [2–4]. Also, after pneumonectomy, RV may mask increases in pulmonary artery pressure and pulmonary vascular resistance by dilating at rest. However, exercise overloads the RV and unmasks a clear elevation in afterload [2]. The heart and remaining lung after pneumonectomy may be physiologically adapted to the normal maximum RV overload after several years. Cardiac function of long-term survivors after pneumonectomy has physiologic pressures and flows at rest, but cardiopulmonary compliance during exercise may be diminished with time.
After pneumonectomy, postoperative changes in subjective symptoms and pulmonary hemodynamics are not always parallel. This discrepancy between cardiopulmonary function and clinical symptoms in long-term follow-up after pneumonectomy may reflect patient adaptation to this unfavorable situation and unconscious self-limitation of daily activities. Longitudinal and comparative analysis will be helpful for examining the long-term effects of pneumonectomy on cardiac function at rest and during exercise.
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References
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- Smulders SA, Holverda S, Vonk-Noordegraaf A, et al. Cardiac function and position more than 5 years after pneumonectomy Ann Thorac Surg 2007;83:1986-1992.[Abstract/Free Full Text]
- Okada M, Ota T, Okada M, Matsuda H, Okada K. Right ventricular dysfunction after major pulmonary resection J Thorac Cardiovas Surg 1994;108:503-511.[Abstract/Free Full Text]
- Miyazawa M, Haniuda M, Nishimura H, Kubo K. Long-term effects of pulmonary resection on cardiopulmonary function J Am Coll Surg 1999;189:26-33.[Medline]
- Kowalewski J, Brocki M, Dryjansk T, Kapron K, Barcikowski S. Right ventricular morphology and function after pulmonary resection Eur J Cardiothorac Surg 1999;15:444-448.[Abstract/Free Full Text]
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Cardiac Function and Position More Than 5 Years After Pneumonectomy
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Ann. Thorac. Surg. 2007 83: 1986-1992.
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[Full Text]
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