Cardiorespiratory Fitness (Peak Oxygen Uptake): Safe and Effective Measure for Cardiovascular Screening Before Kidney Transplant.

BACKGROUND: Significant heterogeneity exists in practice patterns and algorithms used for cardiac screening before kidney transplant. Cardiorespiratory fitness, as measured by peak oxygen uptake (VO2peak), is an established validated predictor of future cardiovascular morbidity and mortality in both healthy and diseased populations. The literature supports its use among asymptomatic patients in abrogating the need for further cardiac testing. METHODS AND RESULTS: We outlined a pre-renal transplant screening algorithm to incorporate VO2peak testing among a population of asymptomatic high-risk patients (with diabetes mellitus and/or >50 years of age). Only those with VO2peak <17 mL/kg per minute (equivalent to <5 metabolic equivalents) underwent further noninvasive cardiac screening tests. We conducted a retrospective study of the a priori dichotomization of the VO2peak <17 versus ≥17 mL/kg per minute to determine negative and positive predictive value of future cardiac events and all-cause mortality. We report a high (>90%) negative predictive value, indicating that VO2peak ≥17 mL/kg per minute is effective to rule out future cardiac events and all-cause mortality. However, lower VO2peak had low positive predictive value and should not be used as a reliable metric to predict future cardiac events and/or mortality. In addition, a simple mathematical calculation documented a cost savings of ≈$272 600 in the cardiac screening among our study cohort of 637 patients undergoing evaluation for kidney and/or pancreas transplant. CONCLUSIONS: We conclude that incorporating an objective measure of cardiorespiratory fitness with VO2peak is safe and allows for a cost savings in the cardiovascular screening protocol among higher-risk phenotype (with diabetes mellitus and >50 years of age) being evaluated for kidney transplant.

Sildenafil and assessment of pulmonary arterial reactivity in heart failure.

Pulmonary hypertension is a daunting accompaniment of advanced heart failure. Efforts to safely and consistently lower pulmonary vascular resistance are necessary but fraught with challenges. In this report the authors explore the novel use of sildenafil, an inhibitor of phosphodiesterase-5, in tackling pulmonary hypertension in heart failure. The salutary effects of this agent deserve further study.

Ethnic disparity in clinical outcome after heart transplantation is abrogated using tacrolimus and mycophenolate mofetil-based immunosuppression.

BACKGROUND: Black American heart transplant recipients receiving cyclosporine-based primary immunoprophylaxis suffer higher rates of allograft rejection with hemodynamic compromise, infections, and posttransplant coronary artery disease. We examined the hypothesis that a combination of tacrolimus and mycophenolate mofetil "resurrects" clinical outcome of black Americans to those seen in white heart transplant recipients. METHODS: Sixty-three adult primary heart transplant recipients were included in this study. Twenty black American and 21 white patients who received tacrolimus-based primary immunoprophylaxis were enrolled in this prospective, observational parallel cohort investigation. A separate group of 22 black American patients were randomly allocated to receive cyclosporine-microemulsion-based primary prophylaxis and served as the control population for assessing outcomes in the black American group. Adjunctive immunosuppression included mycophenolate mofetil and corticosteroids. The primary end-point was the freedom from allograft rejection requiring treatment at 1 year. Secondary end-points included rejection with hemodynamic compromise, and patient or graft survival. Adverse events evaluated included development of infections requiring hospitalization and nonimmunological outcomes including hyperlipidemia, hypertension, and diabetes mellitus (new onset or worsened). RESULTS: Tacrolimus-treated black American patients had greater freedom from allograft rejection requiring treatment at 1 year than those treated with cyclosporine (64% vs. 37%, P=0.01). No differences were noted between tacrolimus-treated black Americans and whites in the primary end point (64% and 67% respectively, P=nonsignificant [NS]). Tacrolimus-based immunosuppression was associated with better 1-year survival in black Americans compared with cyclosporine (95% vs. 73%, P=0.04), and this end point was similar to that achieved in tacrolimus-treated white heart transplant recipients (95%). No differences in infection rates were noted among either group. Cyclosporine-treated black Americans suffered more hyperlipidemia and worse hypertension than tacrolimus-treated patients. CONCLUSIONS: Compared with cyclosporine, an immunosuppressive strategy using tacrolimus in black Americans achieves superior efficacy with regard to allograft rejection, higher allograft survival, and similar safety. Furthermore, tacrolimus-based immunosuppression is similar in immunological efficacy and safety in black Americans and in white heart transplant recipients.