Kevin Marzo

N-Acetylcysteine In The Prevention Of Radiocontrast-Induced Nephropathy

N-acetylcysteine is a remarkably active agent shown to be useful in a variety of clinical settings. The drug has actions relevant to radiocontrast-induced nephropathy (RCIN) that include vasodilatation, enhancement of renal medullary blood flow, and antioxidant properties. The drugs pharmacokinetics are remarkable for almost complete first pass metabolism after oral administration, resulting in no free drug reaching the circulation. After intravenous administration, extensive reaction with tissue and plasma proteins greatly limits the amount of circulating free drug. Given the difficulty achieving free drug in the systemic circulation, it is highly likely that the drug works via its metabolites. The primary mechanism may be through L-cysteine as a cellular source for glutathione production. Clinical studies of N-acetylcysteine in the prevention of RCIN have yielded highly mixed results; five were dramatically positive, and eight others had no demonstrable efficacy at all. The following will review the individual studies, attempt to reconcile the divergent results, and propose future research needs.

Effects of cardiac transplantation on ventilatory response to exercise

Patients with heart failure frequently exhibit an excessive ventilatory response to exercise, which is acutely unaltered by therapeutic interventions. To investigate whether these ventilatory responses resolve after cardiac transplantation, 15 ambulatory patients with severe heart failure underwent exercise testing with measurement of respiratory gases before and 1.4 +/- 0.6 years [corrected] after transplantation. Ventilatory response was also measured in 7 age-matched, sedentary control subjects. Left ventricular ejection fraction at rest and hemodynamic measurements were obtained before and after transplantation in all patients. After transplantation, ejection fraction at rest increased from 16 +/- 6 to 56 +/- 10%, pulmonary capillary wedge pressure declined from 26 +/- 8 to 12 +/- 5 mm Hg, and cardiac index increased from 1.7 +/- 0.5 to 2.8 +/- 0.5 liters/min/m2 (all p less than 0.001). Peak oxygen consumption increased from 11.8 +/- 1.9 to 19.2 +/- 3.1 ml/kg/min (p less than 0.001), but remained significantly lower than that in control subjects (33.4 +/- 6.9 ml/kg/min; p less than 0.01). Minute ventilation (VE) was significantly reduced after transplantation, but excessive compared with normal values. Ventilation at a carbon dioxide production of 1 liter/min decreased significantly after cardiac transplantation (52.1 +/- 7.9 to 38.8 +/- 3.8 liters; p less than 0.01), but remained elevated when contrasted to that in control subjects (31.4 +/- 3.4 liters; p less than 0.05). Ventilatory response to exercise is significantly improved after cardiac transplantation; however, VE remains excessive. This may reflect an attenuated cardiac output response to exercise, abnormal intrapulmonary pressures or persistent deconditioning.

Effect of balloon mitral valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation

OBJECTIVES The short- and long-term effects of valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation were investigated to determine whether a dissociation between hemodynamic improvement and exercise capacity occurs in patients with mitral stenosis. BACKGROUND Percutaneous balloon mitral valvuloplasty in patients with mitral stenosis results in immediate hemodynamic improvement at rest and with exercise. Improved exercise capacity has been described at 3 months after valvuloplasty. In patients with left ventricular dysfunction, acute therapeutic interventions that produce hemodynamic benefit do not immediately improve exercise capacity. METHODS Maximal bicycle exercise with measurement of respiratory gases was performed in 11 patients with mitral stenosis before and at 48 h and 3 months after successful percutaneous balloon mitral valvuloplasty. Respiratory and leg skeletal muscle oxygenation were assessed by monitoring changes in light absorption of the serratus anterior and vastus lateralis muscles using near-infrared spectroscopy and were expressed as percent deoxygenation. RESULTS Mitral valvuloplasty significantly increased mean mitral valve area from 1.0 +/- 0.2 to 1.7 +/- 0.3 cm2 (p < 0.05). Immediately after valvuloplasty, peak exercise oxygen consumption (VO2), VO2 at the anaerobic threshold, ventilation, peak respiratory and leg muscle deoxygenation all remained unchanged. At submaximal work loads, respiratory muscle deoxygenation was attenuated (25 W: before 12 +/- 4%; 48 h 4 +/- 3%; 50 W: before 10 +/- 5%; 48 h 5 +/- 4%; both p < 0.05). At 3 months, significant improvement in peak VO2 (before 10.9 +/- 5%; 3 months 14.6 +/- 6.2 ml/kg per min; p < 0.05) and VO2 at the anaerobic threshold (before 7.1 +/- 2.4; 3 months 8.4 +/- 2.3; p < 0.05) were observed, whereas ventilation remained unchanged. No further improvement was seen in respiratory muscle deoxygenation. Vastus lateralis deoxygenation at submaximal work loads tended to be decreased. CONCLUSIONS Long-term changes in skeletal muscle and the lungs preclude immediate enhancement of exercise performance after balloon mitral valvuloplasty. Immediate symptomatic improvement probably results from an immediate decrease in the work of breathing. Long-term symptomatic improvement results from changes that occur in the peripheral skeletal musculature as well as from the reduced work of breathing.

Impact of severity of renal dysfunction on determinants of in‐hospital mortality among patients undergoing percutaneous coronary intervention

Background: Chronic kidney disease (CKD) is a known prognostic indicator of poor outcomes following percutaneous coronary intervention (PCI) for coronary artery disease. However, it is unclear whether other predictors of mortality differ among patients with varying degrees of renal impairment. Thus, we aimed to identify determinants of in‐hospital mortality which are specific to patients with preserved renal function, moderate CKD, or end stage renal disease (ESRD) on dialysis, undergoing PCI. Methods: The study population included 25,018 patients who underwent PCI between January 1, 2004, and December 31, 2007, at four New York State hospitals. The primary endpoint of the study was in‐hospital mortality. Results: A total of 474 (1.9%) patients had ESRD on dialysis, 6,596 (26.4%) had moderate CKD (GFR<60 ml/min/1.73m2), and 17,948 (71.7%) had preserved renal function (GFR>60 ml/min/1.73m2). Patients with ESRD and moderate CKD were older, more often male, and had higher rates of prior coronary revascularization, peripheral vascular disease, congestive heart failure, prior stroke, and diabetes than those with preserved function. All‐cause in‐hospital mortality rates were significantly higher in patients with ESRD and moderate CKD compared to patients with GFR >60ml/min/1.73m2 (2.1% and 1.3%, respectively vs. 0.3%, p < 0.001). In multivariable analysis, ESRD (OR: 3.68, 95% CI 1.62–8.36) and moderate CKD (OR: 2.92, 95% CI 1.91–4.46) were independently associated with higher rates of in‐hospital mortality. Independent predictors of mortality were markedly distinct in each group and included female gender and myocardial infarction within the past 72 hr in the ESRD group, versus left ventricular ejection fraction, peripheral vascular disease, congestive heart failure, emergency PCI, and absence of prior PCI in the moderate CKD group and age, prior bypass graft surgery, congestive heart failure, emergency PCI, and absence of prior myocardial infarction in patients with preserved renal function Conclusions: Patients with moderate CKD or ESRD undergoing PCI have an approximately threefold increase in the risk of in‐hospital mortality compared with patients with preserved renal function, with radically different mortality predictors existing for varying levels of renal function.

Association of health insurance status with presentation and outcomes of coronary artery disease among nonelderly adults undergoing percutaneous coronary intervention

OBJECTIVE The aim of this study was to determine if insurance status is associated with adverse outcomes in patients with coronary artery disease. METHODS A cohort of 13,456 patients who underwent percutaneous coronary intervention (PCI) between January 1, 2004, and December 31, 2007, at 4 New York State teaching hospitals was retrospectively studied. The primary outcome of interest was in-hospital mortality from any cause. RESULTS Of the 13,456 patients studied, 11,927 (88.6%) were insured by private carriers, 1,036 (7.7%) patients were covered by Medicaid, and 493 (3.7%) were uninsured. Uninsured and Medicaid patients tended to be younger and more often nonwhite and Hispanic. They had a higher prevalence of congestive heart failure and worse left ventricular function. Compared with privately insured patients, uninsured and Medicaid patients had increased all-cause mortality (1.2% and 0.9%, respectively, vs 0.3%; P < .001). For all patients, lack of insurance (OR 3.02, 95% CI 1.10-8.28) and Medicaid (OR 4.39, 95% CI 1.93-9.99) were independently associated with mortality. Lack of insurance (OR 5.02, 95% CI 1.58-15.93) and Medicaid (OR 4.55, 95% CI 1.19-17.45) were also independently associated with increased mortality in patients undergoing emergent PCI. CONCLUSION Lack of insurance and Medicaid insurance are both independently associated with an increased risk of in-hospital mortality after PCI for coronary artery disease.

Patient Awareness of Stent Type, Risk of Cardiac Events, and Symptoms of Myocardial Infarction Among PCI patients: A Missed Educational Opportunity?

BACKGROUND  Timely and successful treatment of myocardial infarction (MI) requires accurate recognition by the patient of the signs and symptoms. As patients who have undergone percutaneous coronary intervention (PCI) remain at risk for cardiac events, it is important that they have a basic understanding of their cardiac status. METHODS  We surveyed 80 consecutive patients following elective PCI using a simple multiple-choice questionnaire. Type of stent (bare metal or drug-eluting), how they perceive the procedure would affect their cardiovascular health, their perceived risk of a future MI, and whether they recalled specific education on how to recognize symptoms of an MI were queried. RESULTS  45% (n = 36) of patients were unaware of stent type. 10% stated PCI was performed to relieve symptoms of angina, 30% (n = 24) stated it would prevent MI, 56.3% (n = 45) stated that it would both prevent MI and reduce symptoms of angina, while 3.8% stated it would do neither. 86.3% (n = 69) stated they remained at risk for MI despite the procedure. However, 42.5% (n = 34) of patients did not perceive to have received specific education on the signs and symptoms of MI during their hospital stay. CONCLUSIONS  Patient understanding of stent type, expected cardiovascular outcomes, and recognition of MI post-PCI appears low in the real-world setting. A systematic approach to post-PCI education should be incorporated into routine care, in order to capitalize on the educational opportunity afforded by this high risk population.

Effect of Gender and Race on Outcomes in Dialysis-Dependent Patients Undergoing Percutaneous Coronary Intervention

We aimed to determine whether gender and race are independently associated with in-hospital major adverse cardiac and cerebrovascular events (MACCE) and hospital length of stay in chronic dialysis patients undergoing percutaneous coronary intervention (PCI). Cardiovascular disease is the leading cause of mortality in patients with end-stage renal disease requiring dialysis. Whether gender or race independently influences the outcomes in patients undergoing PCI is not fully understood. The study population included 474 chronic dialysis patients who underwent PCI at 4 New York State teaching hospitals from January 1, 2004 to December 31, 2007. The primary end point of the study was the composite of in-hospital MACCE, defined as all-cause mortality, nonfatal myocardial infarction, and nonfatal stroke. The secondary end points included in-hospital all-cause mortality and hospital length of stay. Of the 474 chronic dialysis patients, 172 (36.3%) were women. The women undergoing PCI were more likely to be black or Hispanic and had a greater left ventricular ejection fraction. The women had significantly greater rates of in-hospital MACCE (5.8% vs 1.7%, p=0.013) and mortality (4.7% vs 0.7%, p=0.006). No significant difference in the MACCE rates was found between the black and white patients (4.9% vs 2.2%, respectively, p=0.125), although black patients showed a trend toward greater in-hospital mortality (4.1% vs 1.2%, p=0.069). After adjustment for the baseline clinical and procedural characteristics, female gender was an independent predictor of MACCE (odds ratio 7.41, 95% confidence interval 1.81 to 30.27) and all-cause mortality (odds ratio 13.23, 95% confidence interval 1.55 to 113.25), but race was not. No significant difference in the hospital length of stay was observed by either gender or race. In conclusion, in this study, female gender was independently associated with a greater risk of MACCE and all-cause mortality in dialysis-dependent patients undergoing PCI. Although being a black woman was an independent predictor of mortality, race per se was not an independent predictor of in-hospital mortality.

Is intra‐procedure three‐dimensional transesophageal echocardiogram an alternative to preprocedure multidetector computed tomography for the measurement of the aortic annulus in patients undergoing transcatheter aortic valve replacement?

The role of three‐dimensional transesophageal echocardiography (3DTEE) vs multidetector computed tomography (MDCT) in aortic annular sizing has been poorly defined in patients undergoing transcatheter aortic valve replacements (TAVR). We set to determine the correlation between 3DTEE and MDCT in measuring the aortic annulus prior to TAVR.

INCREASED CARDIAC READMISSIONS IN PATIENTS WITH LEFT VENTRICULAR NONCOMPACTION COMPARED TO NONISCHEMIC CARDIOMYOPATHY

Left ventricular noncompaction (LVNC) is an incompletely understood form of cardiomyopathy that can lead to heart failure, ventricular arrhythmias, and sudden cardiac death; however, outcome studies in this disease are lacking. Therefore we examined patients found to have cardiomyopathy by cardiac

ASSESSMENT OF CHANGE IN CLINICAL PRACTICE USING THE UPDATED 2009 AMERICAN COLLEGE OF CARDIOLOGY/ AMERICAN SOCIETY OF NUCLEAR CARDIOLOGY FOR APPROPRIATENESS CRITERIA SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY MYOCARDIAL PERFUSION IMAGING

In 2009 the American College of Cardiology/ American Society of Nuclear Cardiology (ACC/ASNC) updated the 2005 appropriateness criteria categorizing the various indications for the performance of Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT MPI). We sought to