Assessment of left ventricular diastolic function after single lung transplantation in patients with severe pulmonary hypertension

Impact of lung transplantation on diastolic dysfunction in recipients with pretransplant pulmonary hypertension

OBJECTIVE

Pulmonary hypertension can cause left ventricular diastolic dysfunction through ventricular interdependence. Moreover, diastolic dysfunction has been linked to adverse outcomes after lung transplant. The impact of lung transplant on diastolic dysfunction in recipients with pretransplant pulmonary hypertension is not defined. In this cohort, we aimed to assess the prevalence of diastolic dysfunction, the change in diastolic dysfunction after lung transplant, and the impact of diastolic dysfunction on lung transplant outcomes.

METHODS

In a large, single-center database from January 2011 to September 2021, single or bilateral lung transplant recipients with pulmonary hypertension (mean pulmonary artery pressure > 20 mm Hg) were retrospectively identified. Those without a pre- or post-transplant echocardiogram within 1 year were excluded. Diastolic dysfunction was diagnosed and graded according to the American Society of Echocardiography 2016 guideline on assessment of diastolic dysfunction (present, absent, indeterminate). McNemar's test was used to examine association between diastolic dysfunction pre- and post-transplant. Kaplan-Meier and Cox regression analysis were used to assess associations between pre-lung transplant diastolic dysfunction and post-lung transplant 1-year outcomes, including mortality, major adverse cardiac events, and bronchiolitis obliterans syndrome grade 1 or higher-free survival.

RESULTS

Of 476 primary lung transplant recipients, 205 with pulmonary hypertension formed the study cohort (mean age, 56.6 ± 11.9 years, men 61.5%, mean pulmonary artery pressure 30.5 ± 9.8 mm Hg, left ventricular ejection fraction < 55% 9 [4.3%]). Pretransplant, diastolic dysfunction was present in 93 patients (45.4%) (grade I = 8, II = 84, III = 1), absent in 16 patients (7.8%), and indeterminate in 89 patients (43.4%), and 7 patients (3.4%) had missing data. Post-transplant, diastolic dysfunction was present in 7 patients (3.4%) (grade I = 2, II = 5, III = 0), absent in 164 patients (80.0%), and indeterminate in 15 patients (7.3%), and 19 patients (9.3%) had missing data. For those with diastolic dysfunction grades in both time periods (n = 180), there was a significant decrease in diastolic dysfunction post-transplant (148/169 patients with resolved diastolic dysfunction; McNemar's test P < .001). Pretransplant diastolic dysfunction was not associated with major adverse cardiac events (hazard ratio [HR], 1.08, 95% CI, 0.72-1.62; P = .71), bronchiolitis obliterans syndrome-free survival (HR, 0.67, 95% CI, 0.39-1.56; P = .15), or mortality (HR, 0.70, 95% CI, 0.33-1.46; P = .34) at 1 year.

CONCLUSIONS

Diastolic dysfunction is highly prevalent in lung transplant candidates with normal left ventricular systolic function and pulmonary hypertension, and resolves in most patients after lung transplant regardless of patient characteristics. Pre-lung transplant diastolic dysfunction was not associated with adverse lung or cardiac outcomes after lung transplant. Collectively, these findings suggest that the presence of diastolic dysfunction in lung transplant recipients with pulmonary hypertension has no prognostic significance, and as such diastolic dysfunction and the associated clinical syndrome of heart failure with preserved ejection fraction should not be considered a relative contraindication to lung transplant in such patients.

Survival and left ventricular dysfunction post lung transplantation for pulmonary arterial hypertension

PURPOSE

Bilateral lung transplantation for end-stage pulmonary arterial hypertension (PAH) is traditionally associated with higher early post-transplant mortality when compared with other indications. Changes in perioperative management, including the growing use of perioperative extracorporeal membrane oxygenation (ECMO) and an increased awareness of postoperative left ventricular dysfunction (LVD), have resulted in outcomes that are uncertain.

MATERIALS AND METHODS

We conducted a single-center, retrospective observational study at a lung transplantation center in Melbourne, Australia, from 2006 to 2019. ECMO use was categorized as preoperative, prophylactic, or rescue. Postoperative LVD was defined as a reduction in left ventricular function on echocardiography or using strict clinical criteria.

RESULTS

50 patients underwent lung transplantation for PAH. 12-month survival was 48/50 (96%). ECMO was used in 26 (52%) patients, and the use of prophylactic VA-ECMO increased over the study period. Postoperative LVD was diagnosed in 21 (42%) patients. 12-month survival and left ventricular function was no different between LVD and non-LVD groups.

CONCLUSIONS

This study showed that high survival rates can be achieved following lung transplantation for PAH. We found that ECMO utilization was common, and indications have changed over time. LVD was common but did not impact 12-month survival.

Effect of left ventricular diastolic dysfunction on development of primary graft dysfunction after lung transplant

PURPOSE OF REVIEW

Primary graft dysfunction (PGD) is one of the most common complications after lung transplant and is associated with significant early and late morbidity and mortality. The cause of primary graft dysfunction is often multifactorial involving patient, donor, and operational factors. Diastolic dysfunction is increasingly recognized as an important risk factor for development of PGD after lung transplant and here we examine recent evidence on the topic.

RECENT FINDINGS

Patients with end-stage lung disease are more likely to suffer from cardiovascular disease including diastolic dysfunction. PGD as result of ischemia-reperfusion injury after lung transplant is exacerbated by increased left atrial pressure and pulmonary venous congestion impacted by diastolic dysfunction. Recent studies on relationship between diastolic dysfunction and PGD after lung transplant show that patients with diastolic dysfunction are more likely to develop PGD with worse survival outcome and complicated hospital course.

SUMMARY

Patients with diastolic dysfunction is more likely to suffer from PGD after lung transplant. From the lung transplant candidate selection to perioperative and posttransplant care, thorough evaluation and documentation diastolic dysfunction to guide patient care are imperative.

Impact of Left Ventricular Diastolic Dysfunction on Lung Transplantation Outcome in Patients With Pulmonary Arterial Hypertension

Diastolic dysfunction may influence perioperative outcome, early graft function, and long-term survival. We compared the outcomes of double lung transplantation (DLTx) for patients with pulmonary arterial hypertension (PAH) with preoperative left ventricular (LV) diastolic dysfunction with the outcomes of patients without diastolic dysfunction. Of 116 consecutive patients with PAH (who underwent transplantation between January 1995 and December 2013), 44 met our inclusion and exclusion criteria. Fourteen (31.8%) patients with diastolic dysfunction pretransplantation had a higher body mass index (29 [IQR 21.5-32.6] vs 22.4 [IQR 19.9-25.3] kg/m² ) and mean pulmonary arterial pressure (54.6 ± 10 mmHg vs 47 ± 11.3 mmHg) and right atrial pressure (16.5 ± 5.2 mmHg vs 10.6 ± 5.2 mmHg). The patients received extracorporeal life support more frequently (33% vs 7% [p = 0.02]), had worse APACHE II scores (21.7 ± 7.4 vs 15.3 ± 5.3 [p = 0.02]), and a trend toward worse ventilator-free days (2.5 [IQR 6.5-32.5] vs 17 [IQR 3-23] [p = 0.08]). There was no effect on development of primary graft dysfunction or intensive care unit/hospital survival. One-year survival was worse (hazard ratio [HR] 4.45, 95% confidence interval [CI] 1.3-22, p = 0.02). Diastolic dysfunction was the only variable that correlated with overall survival (HR 5.4, 95% CI 1.3-22, p = 0.02). Diastolic dysfunction leads to early postoperative morbidity and worse survival in patients with PAH after DLTx.

Diastolic Dysfunction Increases the Risk of Primary Graft Dysfunction after Lung Transplant

RATIONALE

Primary graft dysfunction (PGD) is a significant cause of early morbidity and mortality after lung transplant and is characterized by severe hypoxemia and infiltrates in the allograft. The pathogenesis of PGD involves ischemia-reperfusion injury. However, subclinical increases in pulmonary venous pressure due to left ventricular diastolic dysfunction may contribute by exacerbating capillary leak.

OBJECTIVES

To determine whether a higher ratio of early mitral inflow velocity (E) to early diastolic mitral annular velocity (é), indicative of worse left ventricular diastolic function, is associated with a higher risk of PGD.

METHODS

We performed a retrospective cohort study of patients in the Lung Transplant Outcomes Group who underwent bilateral lung transplant at our institution between 2004 and 2014 for interstitial lung disease, chronic obstructive pulmonary disease, or pulmonary arterial hypertension. Transthoracic echocardiograms obtained during evaluation for transplant listing were analyzed for E/é and other measures of diastolic function. PGD was defined as PaO2/FiO2 less than or equal to 200 with allograft infiltrates at 48 or 72 hours after reperfusion. The association between E/é and PGD was assessed with multivariable logistic regression.

MEASUREMENTS AND MAIN RESULTS

After adjustment for recipient age, body mass index, mean pulmonary arterial pressure, and pretransplant diagnosis, higher E/é and E/é greater than 8 were associated with an increased risk of PGD (E/é odds ratio, 1.93; 95% confidence interval, 1.02-3.64; P = 0.04; E/é >8 odds ratio, 5.29; 95% confidence interval, 1.40-20.01; P = 0.01).

CONCLUSIONS

Differences in left ventricular diastolic function may contribute to the development of PGD. Future trials are needed to determine whether optimization of left ventricular diastolic function reduces the risk of PGD.

Left Ventricular Dysfunction After Lung Transplantation for Pulmonary Arterial Hypertension

BACKGROUND

Lung transplantation (LT) is the final treatment option for patients with pulmonary arterial hypertension (PAH). Perioperative challenges after LT are unique and commonly include excessive bleeding, arrhythmias, and primary graft dysfunction. Transient left ventricular dysfunction (LVD) is a known postoperative complication, but not fully explored. We describe our experiences at a single institution.

METHODS

We reviewed our database for patients with PAH who underwent LT from July 2008 to July 2012. The data were analyzed for preoperative inotrope use, intravenous prostacyclin, cardiac catheterization, and imaging. Also measured were perioperative ischemic time, bypass time, primary graft dysfunction, ventilator days, length of stay, and mortality. LVD is defined as acute cardiopulmonary compromise (acute worsening of hypoxia with new bilateral infiltrates on imaging) with a drop in LV systolic function of 15% from baseline. We compared data between patients with LVD and without LVD.

RESULTS

Sixteen patients met the criteria, the majority of patients (10) with World Health Organization (WHO) group 1 PAH. Thirteen received intravenous prostacyclin therapy, and 6 required inotropes before surgery. Five patients (31%) developed LVD after transplantation. Average time to onset of LVD was 4.2 days. Preoperative vasopressors were required in 60% of those developing LVD. Patients with LVD had lower right and left ventricular ejection fraction with higher left ventricular end diastolic volume before surgery. All patients recovered from LVD within 4 months after LT.

CONCLUSIONS

LVD is a phenomenon observed mostly in patients with WHO group 1 PAH receiving LT. Prompt recognition and treatment of this condition reduced morbidity.

The striated muscles in pulmonary arterial hypertension: adaptations beyond the right ventricle

Pulmonary arterial hypertension (PAH) is a fatal lung disease characterised by progressive remodelling of the small pulmonary vessels. The daily-life activities of patients with PAH are severely limited by exertional fatigue and dyspnoea. Typically, these symptoms have been explained by right heart failure. However, an increasing number of studies reveal that the impact of the PAH reaches further than the pulmonary circulation. Striated muscles other than the right ventricle are affected in PAH, such as the left ventricle, the diaphragm and peripheral skeletal muscles. Alterations in these striated muscles are associated with exercise intolerance and reduced quality of life. In this Back to Basics article on striated muscle function in PAH, we provide insight into the pathophysiological mechanisms causing muscle dysfunction in PAH and discuss potential new therapeutic strategies to restore muscle dysfunction.

Risk of death and need for transplantation in chronic pulmonary hypertension

BACKGROUND

Echo-Doppler parameters that exemplify right ventricular (RV) outflow dynamics and measures of annular tissue Doppler imaging to assess left ventricular (LV) and RV diastolic function, known to be affected in chronic pulmonary hypertension (cPH), have never been studied to determine if they could be predictive of mortality or need for transplantation 1-year after follow-up.

METHODS

Numerous echo-Doppler parameters of RV and LV performance were recorded from 120 patients. This patient population was divided into 3 groups. Group I had no PH, group II had cPH but no documented death or need for either lung or heart transplantation, at 1-year follow-up after their initial echocardiogram whereas group III had cPH and patients had either died or required heart and/or lung transplantation during the same time period.

RESULTS

Analysis of variance was first used to identify which echo-Doppler variables were significant among the studied groups. A logistic regression analysis was then performed to identify predictive variables of the occurrence death and need for transplantation. Finally, a multiple regression analysis was used between groups II and III to identify which echo-Doppler variables were most useful in identifying severe cPH patients at risk of the prespecified events.

CONCLUSIONS

Even though older patients with worse RV fractional area change might be considered at risk of worse prognosis in patients with severe cPH, only a low mitral annular early diastolic velocity was useful in identifying which of those individuals were at highest risk of death or in need of transplantation.

Role of Transesophageal Echocardiography in Perioperative Patient Management of Lung Transplantation Surgery

Lung transplantation is the only option for patients with end-stage lung disease. Chronic obstructive lung disease, idiopathic pulmonary fibrosis, cystic fibrosis and primary pulmonary hypertension are few common indications for lung transplantation. Patients with end-stage lung disease may have pre-existing cardiovascular compromise related to pulmonary hypertension and other cardiovascular lesions, such as coronary artery disease or valvular heart disease. Preoperative evaluation and optimization of hemodynamics is expected to improve outcomes from lung transplantation. Intraoperative hemodynamic instability is common during lung transplantation and requires highest level of cardiovascular monitoring. After transplantation, vascular anastomosis should be evaluated for flow patterns to rule out obstruction from stenosis or thrombosis. Postoperative complications are common and include bleeding, cardiac failure and hypoxemia from right to left shunt. Primary graft dysfunction may necessitate mechanical cardiorespiratory support. Transesophageal echocardiography plays a central role in preoperative evaluation, intraoperative hemodynamic management, evaluation of pulmonary vascular anastomosis, diagnosis of postoperative complications and also in the critical care management of mechanical cardiorespiratory support.

How to cite this article

Subramaniam K, Esper SA. Role of Transesophageal Echocardiography in Perioperative Patient Management of Lung Transplantation Surgery. J Perioper Echocardiogr 2013;1(2):48-56.

Current pathophysiological concepts and management of pulmonary hypertension

Pulmonary hypertension (PH), increasingly recognized as a major health burden, remains underdiagnosed due mainly to the unspecific symptoms. Pulmonary arterial hypertension (PAH) has been extensively investigated. Pathophysiological knowledge derives mostly from experimental models. Paradoxically, common non-PAH PH forms remain largely unexplored. Drugs targeting lung vascular tonus became available during the last two decades, notwithstanding the disease progresses in many patients. The aim of this review is to summarize recent advances in epidemiology, pathophysiology and management with particular focus on associated myocardial and systemic compromise and experimental therapeutic possibilities. PAH, currently viewed as a panvasculopathy, is due to a crosstalk between endothelial and smooth muscle cells, inflammatory activation and altered subcellular pathways. Cardiac cachexia and right ventricular compromise are fundamental determinants of PH prognosis. Combined vasodilator therapy is already mainstay for refractory cases, but drugs directed at these new pathophysiological pathways may constitute a significant advance.

Prevalence and prognostic value of left ventricular diastolic dysfunction in idiopathic and heritable pulmonary arterial hypertension

BACKGROUND

Little is known about the association between left ventricular (LV) diastolic dysfunction and outcomes in patients with idiopathic or heritable pulmonary arterial hypertension (PAH). Our rationale was to investigate the prevalence of LV diastolic dysfunction, and its association with disease severity and outcomes, in patients with idiopathic or heritable PAH.

METHODS

Using the Cleveland Clinic Pulmonary Hypertension Registry, we identified subjects with heritable or idiopathic PAH who underwent Doppler echocardiography and right-sided heart catheterization. Echocardiographic diastolic parameters were assessed in each patient.

RESULTS

A total of 61 patients met the inclusion criteria (idiopathic 85%, heritable 15%). The age at the time of echocardiography was 48.3 ± 18 years, 84% of the subjects were women, and 48% were on PAH-targeted therapies. Normal LV diastolic function, impaired relaxation, and pseudonormalization were seen in 10%, 88%, and 2% of the patients, respectively. Peak early diastolic (peak E) velocity was directly associated with LV end-diastolic volume and cardiac index and inversely associated with the degree of right ventricular dilation, right atrial pressure, and pulmonary vascular resistance. Peak E velocity was associated with mortality adjusted for age and sex (hazard ratio [HR], 1.5; 95% CI, 1.1-2 per 10 cm/s decrease; P = .015) and age, sex, 6-min walk distance, and cardiac output (HR, 1.8; 95% CI, 1.2-2.9 per 10 cm/s decrease; P = .01).

CONCLUSIONS

LV diastolic dysfunction of the impaired relaxation type is observed in the majority of patients with advanced idiopathic or heritable PAH. A decrease in transmitral flow peak E velocity is associated with worse hemodynamics and outcome.

The effect of pulmonary hypertension on left ventricular diastolic function in chronic obstructive lung disease: a tissue Doppler imaging and right cardiac catheterization study

BACKGROUND

Pulmonary hypertension (PH) caused by chronic obstructive lung disease (COLD) essentially involves the right heart. Also left ventricular (LV) systolic and diastolic functions may be affected.

OBJECTIVES

The aim of this study was to investigate the effect of on LV diastolic function in patients with COLD.

METHODS

A total of 47 patients with COLD and 20 controls were included in this study. All patients underwent Doppler echocardiography, tissue Doppler imaging examinations and right cardiac catheterization. The patients were divided into 2 subgroups according to mean pulmonary arterial pressure (mPAP): patients without PH (group1, n = 25) and with PH (group 2, n = 22). The following measurements were taken: peak velocity of early diastolic filling (E), peak late filling with atrial contraction (A), E/A ratio, deceleration time (DT) of E, isovolumic relaxation time (IVRT), early (Em) and late (Am) diastolic mitral lateral annulus velocity.

RESULTS

Mitral E/A < 1 and Em < 8 cm/sec were higher in group 2 than in group 1 and the control group. There were significant correlations between mPAP and both mitral E/A (r:- 0.60) and Em (r:- 0.45). In multivariate model, mPAP was not found to be significant on mitral E/A ratio < 1, but there was a significant effect on mitral Em < 8 cm/sec (odds ratio [OR]:1.14, P < 0.05).

CONCLUSION

This study shows that LV diastolic dysfunction in COLD is closely correlated to PH levels. Although increased mPAP may affect the mitral E/A ratio, it seems to have no effect on mitral E/A < 1, whereas it has an independent effect on Em < 8 cm/sec.

Time course and mechanisms of left ventricular systolic and diastolic dysfunction in monocrotaline-induced pulmonary hypertension

Although pulmonary hypertension (PH) selectively overloads the right ventricle (RV), neuroendocrine activation and intrinsic myocardial dysfunction have been described in the left ventricle (LV). In order to establish the timing of LV dysfunction development in PH and to clarify underlying molecular changes, Wistar rats were studied 4 and 6 weeks after subcutaneous injection of monocrotaline (MCT) 60 mg/kg (MCT-4, n = 11; MCT-6, n = 11) or vehicle (Ctrl-4, n = 11; Ctrl-6, n = 11). Acute single beat stepwise increases of systolic pressure were performed from baseline to isovolumetric (LVPiso). This hemodynamic stress was used to detect early changes in LV performance. Neurohumoral activation was evaluated by measuring angiotensin-converting enzyme (ACE) and endothelin-1 (ET-1) LV mRNA levels. Cardiomyocyte apoptosis was evaluated by TUNEL assay. Extracellular matrix composition was evaluated by tenascin-C mRNA levels and interstitial collagen content. Myosin heavy chain (MHC) composition of the LV was studied by protein quantification. MCT treatment increased RV pressures and RV/LV weight ratio, without changing LV end-diastolic pressures or dimensions. Baseline LV dysfunction were present only in MCT-6 rats. Afterload elevations prolonged tau and upward-shifted end-diastolic pressure dimension relations in MCT-4 and even more in MCT-6. MHC-isoform switch, ACE upregulation and cardiomyocyte apoptosis were present in both MCT groups. Rats with severe PH develop LV dysfunction associated with ET-1 and tenascin-C overexpression. Diastolic dysfunction, however, could be elicited at earlier stages in response to hemodynamic stress, when only LV molecular changes, such as MHC isoform switch, ACE upregulation, and myocardial apoptosis were present.

Transesophageal Echocardiography During Lung Transplantation

Transesophageal echocardiography (TEE) is a semi-invasive monitoring technique increasingly used in cardiac surgery and in major noncardiac surgery for patients with known or supposed cardiac or coronary problems. During lung transplantation (LTx), the close interrelation between heart and lung function makes TEE an invaluable tool for instantly monitoring the physiopathological situation in the subsequent steps of the intervention. In patients scheduled for LTx, induction of anesthesia could be a dangerous moment with the possibility of cardiogenic shock if pulmonary hypertension (PH) exists; pneumatic tamponade is also possible in patients with emphysema caused by alpha(1)-antitrypsin deficiency, with subsequent cardiac insufficiency. One-lung ventilation is a critical phase during LTx; hypoxemia resulting from ventilation of a diseased dependent lung could impair heart oxygenation, particularly if tachycardia is present. Clamping of the pulmonary artery before pneumonectomy could exacerbate cardiac afterload, especially in patients with previous PH. High transmural pressure, linked with low systemic pressure, makes right ventricle (RV) perfusion pressure inadequate. Hypoxemia and PH are the most frequent causes of intraoperative RV decompensation. In this special setting, TEE is irreplaceable in informing the anesthesiologist about the correct time for extracorporeal oxygenation. Lung reperfusion brings with it the possibility of coronary gaseous embolism, easily detected with TEE. After LTx, TEE can be used to detect strictures, thrombi, or permeability of pulmonary venous anastomoses. To summarize, intraoperative TEE during LTx contributes to the immediate recognition of critical events and allows for rapid therapeutic interventions.

Myocardial dysfunction and neurohumoral activation without remodeling in left ventricle of monocrotaline-induced pulmonary hypertensive rats

In monocrotaline (MCT)-induced pulmonary hypertension (PH), only the right ventricle (RV) endures overload, but both ventricles are exposed to enhanced neuroendocrine stimulation. To assess whether in long-standing PH the left ventricular (LV) myocardium molecular/contractile phenotype can be disturbed, we evaluated myocardial function, histology, and gene expression of autocrine/paracrine systems in rats with severe PH 6 wk after subcutaneous injection of 60 mg/kg MCT. The overloaded RV underwent myocardial hypertrophy ( P < 0.001) and fibrosis ( P = 0.014) as well as increased expression of angiotensin-converting enzyme (ACE) (8-fold; P < 0.001), endothelin-1 (ET-1) (6-fold; P < 0.001), and type B natriuretic peptide (BNP) (15-fold; P < 0.001). Despite the similar upregulation of ET-1 (8-fold; P < 0.001) and overexpression of ACE (4-fold; P < 0.001) without BNP elevation, the nonoverloaded LV myocardium was neither hypertrophic nor fibrotic. LV indexes of contractility ( P < 0.001) and relaxation ( P = 0.03) were abnormal, however, and LV muscle strips from MCT-treated compared with sham rats presented negative ( P = 0.003) force-frequency relationships (FFR). Despite higher ET-1 production, BQ-123 (ETA antagonist) did not alter LV MCT-treated muscle strip contractility distinctly ( P = 0.005) from the negative inotropic effect exerted on shams. Chronic daily therapy with 250 mg/kg bosentan (dual endothelin receptor antagonist) after MCT injection not only attenuated RV hypertrophy and local neuroendocrine activation but also completely reverted FFR of LV muscle strips to positive values. In conclusion, the LV myocardium is altered in advanced MCT-induced PH, undergoing neuroendocrine activation and contractile dysfunction in the absence of hypertrophy or fibrosis. Neuroendocrine mediators, particularly ET-1, may participate in this functional deterioration.

Error estimation of geometrical data obtained by histomorphometry of oblique vessel sections: a computer model study

The errors of radius and wall thickness of a single vessel due to oblique sectioning in histomorphometry are expressed as a function of the circular shape factor (CSF) of the section's lumen, assuming cylindrical geometry and the absence of tissue deformation. Using computer model trees generated by constrained constructive optimization, mean errors are estimated for an ensemble of vessel segments. A geometrical exclusion criterion for segments cut too obliquely is defined on the basis of a CSF-cutoff value. It is shown that CSF-values ranging from 0.95 to 0.9 are reasonable choices for a cutoff and lead to mean errors of the same order of magnitude (9.6% [9.3%] to 15.4% [14.8%] for the radius [wall thickness]) as errors due to histological tissue processing.

Impact of pulmonary hypertension on the outcomes of noncardiac surgery: predictors of perioperative morbidity and mortality

OBJECTIVES

We sought to determine the predictors of short-term morbidity and mortality (< 30 days) after noncardiac surgery in patients with pulmonary hypertension (PH).

BACKGROUND

Pulmonary hypertension is considered to be a significant preoperative risk factor.

METHODS

The PH and surgical data bases were matched from 1991 to 2003. Patients were excluded if PH was secondary to left heart disease, not present before surgery, or the procedure involved cardiopulmonary bypass. Univariate and multivariate logistic regression analyses were used to identify variables associated with short-term morbidity and mortality.

RESULTS

Of 1,276 patients in the PH database, 145 patients (73% female) met all study criteria. The mean age (+/-SD) was 60.1 +/- 16.0 years. Right ventricular systolic pressure (RVSP) (mean +/- SD) on the two-dimensional echocardiogram was 68 +/- 21 mm Hg. There were 60 patients (42%) who experienced one or more short-term morbid event(s) (1.8 events/patient experiencing any event). A history of pulmonary embolism (p = 0.01), New York Heart Association functional class > or = II (p = 0.02), intermediate- to high-risk surgery (p = 0.04), and duration of anesthesia > 3 h (p = 0.04) were independent predictors of short-term morbidity. There were 10 early deaths (7%). A history of pulmonary embolism (p = 0.04), right-axis deviation (p = 0.02), right ventricular (RV) hypertrophy (p = 0.04), RV index of myocardial performance > or = 0.75 (p = 0.03), RVSP/systolic blood pressure > or = 0.66 (p = 0.01), intraoperative use of vasopressors (p < 0.01), and anesthesia when nitrous oxide was not used (p < 0.01) were each associated with postoperative mortality.

CONCLUSIONS

In patients with PH undergoing noncardiac surgery with general anesthesia, specific clinical, diagnostic, and intraoperative factors may predict worse outcomes.

Impact of acute hypoxic pulmonary hypertension on LV diastolic function in healthy mountaineers at high altitude

In pulmonary hypertension right ventricular pressure overload leads to abnormal left ventricular (LV) diastolic function. Acute high-altitude exposure is associated with hypoxia-induced elevation of pulmonary artery pressure particularly in the setting of high-altitude pulmonary edema. Tissue Doppler imaging (TDI) allows assessment of LV diastolic function by direct measurements of myocardial velocities independently of cardiac preload. We hypothesized that in healthy mountaineers, hypoxia-induced pulmonary artery hypertension at high altitude is quantitatively related to LV diastolic function as assessed by conventional and TDI Doppler methods. Forty-one healthy subjects (30 men and 11 women; mean age 41 ± 12 yr) underwent transthoracic echocardiography at low altitude (550 m) and after a rapid ascent to high altitude (4,559 m). Measurements included the right ventricular to right atrial pressure gradient (ΔPRV-RA), transmitral early ( E) and late ( A) diastolic flow velocities and mitral annular early ( Em) and late ( Am) diastolic velocities obtained by TDI at four locations: septal, inferior, lateral, and anterior. At a high altitude, ΔPRV-RA increased from 16 ± 7to44 ± 15 mmHg ( P < 0.0001), whereas the transmitral E-to- A ratio ( E/ A ratio) was significantly lower (1.11 ± 0.27 vs. 1.41 ± 0.35; P < 0.0001) due to a significant increase of A from 52 ± 15 to 65 ± 16 cm/s ( P = 0.0001). ΔPRV-RA and transmitral E/ A ratio were inversely correlated ( r2 = 0.16; P = 0.0002) for the whole spectrum of measured values (low and high altitude). Diastolic mitral annular motion interrogation showed similar findings for spatially averaged (four locations) as well as for the inferior and septal locations: Am increased from low to high altitude (all P < 0.01); consequently, Em/ Am ratio was lower at high versus low altitude (all P < 0.01). These intraindividual changes were reflected interindividually by an inverse correlation between ΔPRV-RA and Em/ Am (all P < 0.006) and a positive association between ΔPRV-RA and Am (all P < 0.0009). In conclusion, high-altitude exposure led to a two- to threefold increase in pulmonary artery pressure in healthy mountaineers. This acute increase in pulmonary artery pressure led to a change in LV diastolic function that was directly correlated with the severity of pulmonary hypertension. However, in contrast to patients suffering from some form of cardiopulmonary disease and pulmonary hypertension, in these healthy subjects, overt LV diastolic dysfunction was not observed because it was prevented by augmented atrial contraction. We propose the new concept of compensated diastolic (dys)function.

Effects of the oral endothelin-receptor antagonist bosentan on echocardiographic and doppler measures in patients with pulmonary arterial hypertension

OBJECTIVES

The purpose of this study was to investigate the effects of bosentan (125 or 250 mg twice daily) on echocardiographic and Doppler variables in 85 patients with World Health Organization class III or IV pulmonary arterial hypertension (PAH).

BACKGROUND

Bosentan, an orally active dual endothelin-receptor antagonist, improves symptoms, exercise capacity, and hemodynamics in patients with PAH.

METHODS

Patients had primary pulmonary hypertension (84%) or PAH associated with connective tissue disease. Of these, 29 patients received placebo and 56 received bosentan (1:2 randomization). Six-minute walk tests and echocardiograms were performed at baseline and after 16 weeks of treatment.

RESULTS

Baseline characteristics were similar in the placebo and bosentan groups, and echocardiographic and Doppler findings were consistent with marked abnormalities of right ventricular (RV) and left ventricular (LV) structure and function that were due to PAH. The treatment effect on 6-min walking distance was 37 m in favor of bosentan (p = 0.036). Treatment effects of bosentan compared with placebo on other parameters were as follows: Doppler-derived cardiac index = +0.4 l/min/m(2) (p = 0.007), LV early diastolic filling velocity = +10.5 cm/s (p = 0.003), LV end-diastolic area = +4.2 cm(2) (p = 0.003), LV systolic eccentricity index = -0.12 (p = 0.047), RV end-systolic area = -2.3 cm(2) (p = 0.057), RV:LV diastolic areas ratio = -0.64 (p = 0.007), Doppler RV index = -0.06 (p = 0.03), and percentage of patients with an improvement in pericardial effusion score = 17% (p = 0.05).

CONCLUSIONS

Bosentan improves RV systolic function and LV early diastolic filling and leads to a decrease in RV dilation and an increase in LV size in patients with PAH.