Prevalence of exertional oscillatory ventilation in continuous-flow left ventricular assist device recipients.

BACKGROUND: Exercise oscillatory ventilation is an ominous outcome sign in heart failure due to reduced left ventricular ejection fraction; currently, the prevalence of exercise oscillatory ventilation is unknown in left ventricular assist device recipients. METHODS: We studied cardiopulmonary exercise testing in heart failure due to reduced left ventricular ejection fraction or left ventricular assist device patients and exercise oscillatory ventilation was defined according to Kremser's criteria. RESULTS: The occurrence of exercise oscillatory ventilation was similar in either heart failure due to reduced left ventricular ejection fraction (192 patients, 8%) or left ventricular assist device patients (85 recipients, 10%), even though the mean peak oxygen consumption and elevated ventilatory response to exercise slope was lower and higher in left ventricular assist device recipients, respectively, but the occurrence of exercise oscillatory ventilation was comparable among heart failure patients due to reduced left ventricular ejection fraction and left ventricular assist device, if those with impaired exercise capacity were considered. Of note, left ventricular assist device recipients with exercise oscillatory ventilation had a higher end-diastolic left ventricular volume and systolic pulmonary artery pressure at rest. CONCLUSIONS: Using the largest cohort of left ventricular assist device patients performing cardiopulmonary exercise testing, we demonstrated that the occurrence of exercise oscillatory ventilation is similar in heart failure due to reduced left ventricular ejection fraction and left ventricular assist device patients. Recipients with exercise oscillatory ventilation might have haemodynamic and ventilatory dysfunction during exercise, but other factors could play a role, i.e. the duration and severity of heart failure before left ventricular assist device implantation together with the coexistence of morbidity.

Exercise gas exchange in continuous-flow left ventricular assist device recipients.

Exercise ventilation/perfusion matching in continuous-flow left ventricular assist device recipients (LVAD) has not been studied systematically. Twenty-five LVAD and two groups of 15 reduced ejection fraction chronic heart failure (HFrEF) patients with peak VO2 matched to that of LVAD (HFrEF-matched) and ≥14 ml/kg/min (HFrEF≥14), respectively, underwent cardiopulmonary exercise testing with arterial blood gas analysis, echocardiogram and venous blood sampling for renal function evaluation. Arterial-end-tidal PCO2 difference (P(a-ET)CO2) and physiological dead space-tidal volume ratio (VD/VT) were used as descriptors of alveolar and total wasted ventilation, respectively. Tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio (TAPSE/PASP) and blood urea nitrogen/creatinine ratio were calculated in all patients and used as surrogates of right ventriculo-arterial coupling and circulating effective volume, respectively. LVAD and HFrEF-matched showed no rest-to-peak change of P(a-ET)CO2 (4.5±2.4 vs. 4.3±2.2 mm Hg and 4.1±1.4 vs. 3.8±2.5 mm Hg, respectively, both p >0.40), whereas a decrease was observed in HFrEF≥14 (6.5±3.6 vs. 2.8±2.0 mm Hg, p <0.0001). Rest-to-peak changes of P(a-ET)CO2 correlated to those of VD/VT (r = 0.70, p <0.0001). Multiple regression indicated TAPSE/PASP and blood urea nitrogen/creatinine ratio as independent predictors of peak P(a-ET)CO2. LVAD exercise gas exchange is characterized by alveolar wasted ventilation, i.e. hypoperfusion of ventilated alveoli, similar to that of advanced HFrEF patients and related to surrogates of right ventriculo-arterial coupling and circulating effective volume.

How to face emergencies in heart failure patients with ventricular assist device.

Ventricular assist device (VAD) technology has rapidly evolved, and VADs are now seen as a reliable lifesaving option to support the failing heart in the short- and long-term: in some cases, VAD therapy represents a well-accepted treatment option for advanced heart failure that can obviate the need for heart transplantation. In the near future, more and more cardiologists will encounter VAD patients in their clinical practice and need to know how to handle the inherent risks associated with VAD use. The emergency care of a VAD patient differs from that of conventional practice and specific expertise is required to avoid inappropriate management that could lead to inefficient treatment and/or dangerous consequences. Here, we describe two emergency scenarios in VAD patients, two paradigmatic clinical in-hospital situations, in different settings. Following a brief overview of the role of cardiopulmonary resuscitation maneuvers in VAD patients, we propose a working algorithm that might help to ensure a timely and efficient response to acute demands in this setting.

Cardiovascular prevention and rehabilitation for patients with ventricular assist device from exercise therapy to long-term therapy. Part II: long-term therapy.

Over the years left ventricular assist devices (VADs) have become more durable and reliable, smaller, simpler, easier to implant and more comfortable. The extensive experience now acquired shows successful hospital discharge with VAD use. We are entering an era in which long-term mechanical circulatory support will play an increasing role in the approach to end-stage heart failure (HF); at the same time, the extension of VADs into destination therapy has revealed the limitations of our understanding of these populations. This second paper on cardiovascular prevention and rehabilitation for patients with left VADs will deal with the management of patients outside the highly specialized HF centers and surgical setting, with particular focus on postoperative patient management. Outpatient management of VAD patients is time-intensive, and a multidisciplinary approach is ideal in long-term care. Although the new devices have definite advantages over the older pumps, some challenges still remain, i.e. infection, stroke, device thrombosis, gastrointestinal bleeding, recurrent HF symptomatology with or without multisystem organ failure, and occurrence of ventricular arrhythmias.

Doppler echocardiography in advanced systolic heart failure: a noninvasive alternative to Swan-Ganz catheter.

BACKGROUND: Although several studies have demonstrated a good correlation between Doppler echocardiographic and invasive measurements of single hemodynamic variables, the accuracy of echocardiography in providing a comprehensive assessment in individual patients has not been validated. The aim of this study was to assess the accuracy and clinical applicability of Doppler echocardiography in determining the entire hemodynamic profile in stable patients with advanced systolic heart failure. METHODS AND RESULTS: Doppler echocardiography and Swan-Ganz catheterization were simultaneously performed in 43 consecutive patients with advanced heart failure. Echocardiographic data required for estimation of right atrial, pulmonary artery systolic, and pulmonary capillary wedge pressures; cardiac output; and pulmonary vascular resistance were obtained and compared with hemodynamic data. For all variables, invasive and noninvasive hemodynamic values were highly correlated (P<0.0001), with very low bias and narrow 95% confidence limits. In 16 patients with elevated pulmonary vascular resistance (>3 Wood U) and pulmonary capillary wedge pressures (>20 mm Hg) at baseline, hemodynamic and Doppler measurements were simultaneously repeated after unloading manipulations. Absolute values and changes of pulmonary vascular resistance and pulmonary capillary wedge pressures after unloading were still accurately predicted (r =0.96 and r =0.92, respectively). CONCLUSIONS: Doppler echocardiography may offer a valid alternative to invasive cardiac catheterization for the comprehensive hemodynamic assessment of patients with advanced heart failure, and it may assist in monitoring and optimization of therapy in potential heart transplant recipients.

Perioperative and postoperative predictors of outcome in patients with low ejection fraction early after coronary artery bypass grafting: the additional value of left ventricular remodeling.

BACKGROUND: Scant data exist on factors that may identify outcome in patients with severe left ventricular (LV) dysfunction early after coronary artery bypass graft surgery (CABG). DESIGN: This study was designed to determine the prognostic value of clinical, operative, and postoperative factors in patients with LV dysfunction early after CABG. METHODS: In 333 consecutive patients with ejection fraction < or =35% on admission to residential cardiac rehabilitation after isolated CABG, potential preoperative, perioperative, and postoperative predictors of outcome, including 6-month LV remodeling, were recorded and patients followed up for a median of 3 years. The study end points were cardiovascular (CV) mortality and the combination of CV mortality and nonfatal CV events requiring hospitalization. RESULTS: The 3-year CV mortality-free survival and survival free of nonfatal CV event rates were 87 and 73%, respectively. Independent predictors of CV mortality were history of congestive heart failure [hazard ratio, HR: 2.8; 95% Confidence Interval (CI): 1.51-5.21], low ejection fraction on admission to cardiac rehabilitation (HR: 0.9; 95% CI: 0.87-0.96), and early complications after CABG (HR: 2.5; 95% CI: 1.23-5.15). When the combined end points were considered, postoperative left atrial size (HR: 1.07; 95% CI: 1.01-1.11), New York Heart Association class III or IV (HR: 1.69; 95% CI: 1.04-2.74), and 6-month remodeling (HR: 2.12; 95% CI: 1.33-3.36) were independent predictors. CONCLUSION: Simple preoperative and postoperative variables may help identify patients with LV dysfunction early after CABG who are still at risk of major CV events. In this setting, 6-month LV remodeling is a strong predictor of a poor prognosis.

Low plasma levels of brain natriuretic peptide in severe acute heart failure: merely a case?

Brain natriuretic peptide (BNP) is commonly used for diagnosis and prognosis of patients with congestive heart failure (HF). High levels of BNP are associated with high probability of cardiogenic dyspnea and higher risk of subsequent cardiovascular events. We describe a case of acute HF (worsening chronic HF) in a 74-year-old male with low plasma BNP levels on admission, in whom a rapid and consistent increase in the marker's concentration occurred after administration of diuretics and vasodilators, despite a prompt clinical and hemodynamic improvement. Reports of cardiogenic dyspnea with moderate increase or normal plasma levels of BNP have been recently published: does this signify a pitfall for BNP as a useful diagnostic and prognostic tool? Clinical implications of our observation are discussed, and we conclude that neurohumoral biomarkers do not obviate the need for a careful physical and instrumental examination of patient.

Ventilatory response to exercise improves risk stratification in patients with chronic heart failure and intermediate functional capacity.

BACKGROUND: Peak oxygen consumption (VO2) has an important prognostic role in chronic heart failure (CHF), but its discriminatory power is limited in patients with intermediate exercise capacity (peak VO2 between 10-18 mL/kg/min). Thus, supplementary exertional indexes are greatly needed. METHODS: Six hundred patients with CHF with left ventricular ejection fraction (LVEF) < or = 40% who performed a symptom-limited cardiopulmonary exercise testing were screened and followed up for 780 +/- 450 days. RESULTS: Eighty-seven patients had major cardiac events (77 cardiac deaths and 10 urgent heart transplantations). Multivariate analysis revealed the rate of increase of minute ventilation per unit of increase of carbon dioxide production (VE/VCO2 slope) (chi2, 79.3, P <.0001), LVEF (chi2, 24.6, P <.0001), and peak VO2 (chi2, 9.4, P <.0001) as independent and additional predictors of major cardiac events. VE/VCO2 slope was the strongest independent predictor of outcome (chi2, 20.9, P =.0001) in patients with intermediate peak VO2 (n = 403), and the best cutoff value was 35 (chi2, 25.8; relative risk = 3.2, 95% CI 2.0-5.1, P <.0001). Total mortality rate was 30% in patients with VE/VCO2 slope > or = 35 (n = 103, 26%) and 10% in those with VE/VCO2 slope <35 (n = 300, 74%) (P <.0001). Patients with VE/VCO2 slope > or = 35 had a similar total mortality rate to those with peak VO2 < or = 10 mL/kg/min (30% vs 37%, P not significant). CONCLUSIONS: A rational and pragmatic risk stratification process with symptom-limited cardiopulmonary exercise testing in CHF should include both peak VO2 and VE/VCO2 slope, the latter index effectively predicting outcome in almost one fourth of patients with intermediate exercise capacity.