Longterm effects of pulmonary resection on cardiopulmonary function

Pulmonary artery wave reflection and right ventricular function after lung resection

BACKGROUND

Lung resection has been shown to impair right ventricular function. Although conventional measures of afterload do not change, surgical ligation of a pulmonary artery branch, as occurs during lobectomy, can create a unilateral proximal reflection site, increasing wave reflection (pulsatile component of afterload) and diverting blood flow through the contralateral pulmonary artery. We present a cardiovascular magnetic resonance imaging (MRI) observational cohort study of changes in wave reflection and right ventricular function after lung resection.

METHODS

Twenty-seven patients scheduled for open lobectomy for suspected lung cancer underwent cardiovascular MRI preoperatively, on postoperative Day 2, and at 2 months. Wave reflection was assessed in the left and right pulmonary arteries (operative and non-operative, as appropriate) by wave intensity analysis and calculation of wave reflection index. Pulmonary artery blood flow distribution was calculated as percentage of total blood flow travelling in the non-operative pulmonary artery. Right ventricular function was assessed by ejection fraction and strain analysis.

RESULTS

Operative pulmonary artery wave reflection increased from 4.3 (2.1-8.8) % preoperatively to 9.5 (4.9-14.9) % on postoperative Day 2 and 8.0 (2.3-11.7) % at 2 months (P<0.001) with an associated redistribution of blood flow towards the nonoperative pulmonary artery (r>0.523; P<0.010). On postoperative Day 2, impaired right ventricular ejection fraction was associated with increased operative pulmonary artery wave reflection (r=-0.480; P=0.028) and pulmonary artery blood flow redistribution (r=-0.545; P=0.011). At 2 months, impaired right ventricular ejection fraction and right ventricular strain were associated with pulmonary artery blood flow redistribution (r=-0.634, P=0.002; r=0.540, P=0.017).

CONCLUSIONS

Pulsatile afterload increased after lung resection. The unilateral increase in operative pulmonary artery wave reflection resulted in redistribution of blood flow through the nonoperative pulmonary artery and was associated with right ventricular dysfunction.

CLINICAL TRIAL REGISTRATION

NCT01892800.

Pulmonary hypertension after pneumonectomy: a preclinical model in rats and human pulmonary endothelial cells

OBJECTIVES

Pulmonary hypertension and heart disease contribute to the high morbidity rate following pneumonectomy (PN). The pathophysiology is still poorly understood. The objective was to investigate the consequences of PN on cardiopulmonary function in rats and to explore in vitro the involved mechanisms.

METHODS

Sixty Sprague-Dawley male rats randomly underwent either a right PN (PN group) or sham surgery. Ten rats per group were sacrificed on postoperative days 3, 7 and 28. Cardiopulmonary alterations were investigated by echocardiographic, haemodynamic and histological analyses. In vitro, the shear stress was reproduced using a Flexcell Tension™ cyclic stretch on cultured human pulmonary endothelial cells (P-ECs) to investigate the impact on pulmonary artery smooth muscle cell (PA-SMC) growth. Data are expressed as mean ± SD.

RESULTS

Mean pulmonary arterial pressure gradually increased in the PN group to reach 35 ± 7 mmHg on postoperative day 28 vs 18 ± 4 in sham (P = 0.001), likewise the proportion of muscularized distal pulmonary arteries, 83 ± 1% vs 5 ± 1%, respectively (P < 0.001), related to in situ PA-SMC proliferation. The right ventricle area and lateral wall thickness were doubled in the PN group on postoperative day 28. The left ventricle ejection fraction decreased on postoperative days 7 and 28 while the right ventricle function was maintained. In vitro, the human PA-SMC growth was significantly greater when seeded with stretched vs non-stretched P-EC media, highlighting the role of shear stress on the P-EC paracrine function.

CONCLUSIONS

Right PN led to pulmonary hypertension and proportional right heart remodelling in rats. The shear stress related to high blood flow alters the pulmonary endothelial paracrine control of SMC growth.

Our current understanding of and approach to the management of lung cancer with pulmonary hypertension

INTRODUCTION

Lung cancer is a frequent pathology for which the best curative treatment is pulmonary resection. Pulmonary arterial hypertension is a rare disease but pulmonary hypertension associated with parenchymal disease or left heart disease is frequently observed in these patients. The diagnosis of pulmonary hypertension before lung resection makes the perioperative management of these patients more difficult and sometimes leads to rejecting patients for surgery.

AREAS COVERED

We performed a review of literature on PubMed on Pulmonary hypertension associated lung resection, preoperative assessment of lung resection and perioperative management of PH patients, including guidelines and clinical trials.In this review, we summarize the current state of knowledge regarding the pre and perioperative management of patients with suspected or confirmed PH who can benefit from surgical treatment of lung cancer.

EXPERT OPINION

Management of PH patients before lung resection should include a very careful workup including at least right heart catheterization with evaluation of the targeted PH treatment in an expert center and evaluation of other comorbidities. Perioperative management must be carried out in a specialized center.

The right ventricular response to lung resection

OBJECTIVES

Lung cancer is a leading cause of cancer death and in suitable cases the best chance of cure is offered by surgery. Lung resection is associated with significant postoperative cardiorespiratory morbidity, with dyspnea and reduced functional capacity as dominant features. These changes are poorly associated with deterioration in pulmonary function and a potential role of right ventricular (RV) dysfunction has been hypothesized. Cardiovascular magnetic resonance imaging is a reference method for noninvasive assessment of RV function and has not previously been applied to this population.

METHODS

We used cardiovascular magnetic resonance imaging to assess the RV response to lung resection. Cardiovascular magnetic resonance imaging with volume and flow analysis was performed on 27 patients preoperatively, on postoperative day 2 and at 2 months. Left ventricular ejection fraction and RV ejection fraction, the ratio of stroke volume to end systolic volume, pulmonary artery acceleration time, and distensibility of main and branch pulmonary arteries were studied.

RESULTS

Mean ± standard deviation RV ejection fraction deteriorated from 50.5% ± 6.9% preoperatively to 45.6% ± 4.5% on postoperative day 2 and remained depressed at 44.9% ± 7.7% by 2 months (P = .003). The ratio of stroke volume to end systolic volume deteriorated from median 1.0 (quartile 1, quartile 3: 0.9, 1.2) preoperatively to median 0.8 (quartile 1, quartile 3: 0.7, 1.0) on postoperative day 2 (P = .011). On postoperative day 2 there was a decrease in pulmonary artery acceleration time and operative pulmonary artery distensibility (P < .030 for both). There were no changes in left ventricular ejection fraction during the study period (P = .621).

CONCLUSIONS

These findings suggest RV dysfunction occurs following lung resection and persists 2 months after surgery. The deterioration in the ratio of stroke volume to end systolic volume suggests a mismatch between afterload and contractility. There is an increase in indices of pulsatile afterload resulting from the operative pulmonary artery.

Pulmonary hypertension after pneumonectomy for lung cancer

Background

We aimed to consolidate our clinical observations regarding the development of pulmonary hypertension following pneumonectomy for lung cancer.

Methods

Sixty-nine of 82 initially selected patients without pulmonary or cardiac comorbidities, who underwent pneumonectomy for lung cancer between October 2009 and October 2011, accomplished our protocol. Mean patient age was 60.6 years (range 44–78 years) and 10.1% were women.

Results

Postoperative complications occurred in 16 (23.2%) patients. Mortality at 1, 12, and 18 months postoperatively was 4.3%, 15.9%, and 29%, respectively. One year postoperatively, 37.9% of patients developed mild to moderate pulmonary hypertension and 3.4% had severe pulmonary hypertension. The calculated mean pulmonary artery systolic pressure at 1, 6, and 12 months postoperatively was 21.9 ± 6.6, 27.3 ± 9.3, and 34.1 ± 14 mm Hg, respectively ( p < 0.001). Receiver operating characteristic curve analysis showed a cutoff point at 35.5 mm Hg for late postoperative (at 12 months) pulmonary artery systolic pressure (sensitivity 80%, specificity 82%; p < 0.001) related to suboptimal clinical outcomes (decreased performance status or death), with a detected 18-fold risk for these patients ( p < 0.001).

Conclusions

Pulmonary hypertension may occur after pneumonectomy with its known adverse effects. Patients with late postoperative pulmonary artery systolic pressure > 35.5 mm Hg are at higher risk of a suboptimal clinical outcome.

Anesthetic management of the patient with dilated cardiomyopathy undergoing pulmonary resection surgery: a case-based discussion

Interactions between the cardiovascular and respiratory systems are complex and profound. General anesthesia, muscle relaxation, and positive-pressure ventilation all impose physiological effects on cardiovascular function. In patients presenting for pulmonary resection, additional effects resulting from positioning, 1-lung ventilation, surgical procedures, and contraction of the pulmonary vascular bed may impose an additional physiological burden. For most patients with adequate pulmonary and cardiovascular reserve, these effects are well tolerated. However, the cardiothoracic anesthesiologist may be asked to provide anesthetic care for patients with significantly reduced cardiac function who require potentially curative pulmonary resection for lung cancer. These patients present a major perioperative challenge and a thoughtful approach to intraoperative management is required. The authors review a case of a patient with severely impaired biventricular function who presented for elective pulmonary lobectomy in an attempt to effect a curative resection of lung cancer and present a discussion of physiological and pathophysiological considerations for clinical management.

The impact of adjuvant brachytherapy with sublobar resection on pulmonary function and dyspnea in high-risk patients with operable disease: preliminary results from the American College of Surgeons Oncology Group Z4032 trial

BACKGROUND

Z4032 was a randomized study conducted by the American College of Surgeons Oncology Group comparing sublobar resection alone versus sublobar resection with brachytherapy for high-risk operable patients with non-small cell lung cancer (NSCLC). This evaluates early impact of adjuvant brachytherapy on pulmonary function tests, dyspnea, and perioperative (30-day) respiratory complications in this impaired patient population.

METHODS

Eligible patients with stage I NSCLC tumors 3 cm or smaller were randomly allocated to undergo sublobar resection with (SRB group) or without (SR group) brachytherapy. Outcomes measured included the percentage predicted forced expiratory volume in 1 second (FEV1%), percentage predicted carbon monoxide diffusion capacity (DLCO%), and dyspnea score per the University of California San Diego Shortness of Breath Questionnaire. Pulmonary morbidity was assessed per the Common Terminology Criteria for Adverse Events version 3.0. Outcomes were measured at baseline and 3 months. A 10% change in pulmonary function test or 10-point change in dyspnea score was deemed clinically meaningful.

RESULTS

Z4032 permanently closed to patient accrual in January 2010 at 224 patients. At 3-month follow-up, pulmonary function data are currently available for 148 (74 SR and 74 SRB) patients described in this report. There were no differences in baseline characteristics between arms. In the SR arm, 9 patients (12%) reported grade 3 respiratory adverse events, compared with 12 (16%) in the SRB arm (P = .49). There was no significant change in percentage change in DLCO% or dyspnea score from baseline to 3 months within either arm. In the case of FEV1%, percentage change from baseline to 3 months was significant within the SR arm (P = .03), with patients reporting improvement in FEV1% at month 3. Multivariable regression analysis (adjusted for baseline values) showed no significant impact of treatment arm, tumor location (upper vs other lobe), or surgical approach (video-assisted thoracoscopic surgery vs thoracotomy) on 3-month FEV1%, DLCO%, and dyspnea score. There was no significant difference in incidence of clinically meaningful (10% pulmonary function or 10-point dyspnea score change) change between arms. Twenty-two percent of patients with lower-lobe tumors and 9% with upper-lobe tumors demonstrated 10% decline in FEV1% (odds ratio, 2.79; 95 confidence interval, 1.07-7.25; P = .04).

CONCLUSIONS

Adjuvant intraoperative brachytherapy in conjunction with sublobar resection did not significantly worsen pulmonary function or dyspnea at 3 months in a high-risk population with NSCLC, nor was it associated with increased perioperative pulmonary adverse events. Lower-lobe resection was the only factor significantly associated with clinically meaningful decline in FEV1%.

Preoperative pulmonary function as a prognostic factor for stage I non–small cell lung carcinoma

BACKGROUND

The aim of this study was to clarify preoperative lung function as a prognostic factor for the long-term survival of, and to discuss the appropriateness of lobectomy for, patients with stage I non-small cell lung carcinoma who have poor preoperative pulmonary function.

METHODS

The study group consisted of 402 lobectomized patients with stage I non-small cell lung carcinoma treated by complete resection from 1985 to 1997. Preoperative percent forced vital capacity [(forced vital capacity/predicted forced vital capacity) x 100], FEV(1)% [(forced expiratory volume in 1 second/forced vital capacity) x 100], arterial carbon dioxide tension, and smoking were statistically analyzed as prognostic factors together with other host and tumor biologic factors.

RESULTS

Multivariate analysis demonstrated that tumor size (p < 0.0001) was the most significant prognostic factor for survival from primary lung cancer. Age (p < 0.0001), sex (p = 0.0036), and FEV(1)% (p = 0.0046) were found to be independent prognostic factors for survival from death by nonprimary lung cancer-related causes. Smoking was highly correlated with FEV(1)% (correlation coefficient = -0.511; p < 0.0001). The 100 patients with a preoperative FEV(1)% less than 70% included 34 patients with nonprimary lung cancer-related deaths, whereas the 302 patients with an FEV(1)% of 70% or greater included only 23 patients (p < 0.0001).

CONCLUSIONS

Along with tumor size, FEV(1)% is the most significant prognostic factor for patients with stage I non-small cell lung carcinoma with regard to survival from death by other causes. Lobectomy may not be preferred as an appropriate surgical modality for patients with stage I non-small cell lung carcinoma with small peripheral nodules who exhibit poor pulmonary function, especially lowered FEV(1)%.

The quality of quality of life studies in general surgical journals

BACKGROUND

There has been a tremendous increase in interest on quality of life in surgical research. An increase in interest does not necessarily translate into better research. This study evaluates surgical articles that claim to measure or make some conclusion on quality of life.

STUDY DESIGN

All articles published in the calendar years 1996 and 1999 that purported to assess quality of life as end points or make some conclusion about quality of life were chosen for review from eight general surgical journals. Articles were assessed for use of a quality of life instrument, type of instrument, validation of the instrument, appropriateness of the instrument for the hypothesis, quality of statistical analysis, and adherence to the Gill and Feinstein criteria.

RESULTS

Of the 18 articles published in 1996, 72% used a quality of life instrument. Eighteen instruments were used in 13 studies: 7 generic, 10 disease-specific, and 1 ad hoc. Forty-three percent were validated, 39% were appropriate for the study hypothesis, 39% had correct statistical analysis. The majority did not meet the Gill and Feinstein criteria. Of the 24 studies published in 1999, 63% used a quality of life instrument. Twenty-two instruments were used in 15 studies: 11 generic, 5 disease-specific, and 6 ad hoc. Fifty-five percent were validated, 45% were appropriate, 45% had correct statistical analysis. Once again, the majority did not meet the Gill and Feinstein criteria.

CONCLUSIONS

Despite the emphasis on quality of life outcomes, a substantial number of studies made errors in conceptually defining quality of life and in use of quality of life instruments. Researchers and journal reviewers need to be better versed on the techniques of quality of life research.