Noninvasive calibration of cardiac pressure transducers in patients with heart failure: an aid to implantable hemodynamic monitoring and therapeutic guidance.

BACKGROUND: Implantable cardiac pressure monitors require assurance of calibration. This study evaluated if airway pressure responses during Valsalva maneuver (VM) can be used for calibrating intracardiac pressure transducers. METHODS AND RESULTS: Thirty-eight heart failure patients performed VMs while cardiac and airway pressures were recorded. Patients were designated as Lower (L) if baseline PCW was <20 mm Hg (n = 17); otherwise, they were categorized as Higher (H) (n = 21). VMs were repeated in 9 H patients after nitroglycerin. Procedural success was 92% and there were no complications. Differences between filling pressure and airway pressure (effective pressure) were eliminated during VM (RA(eff) = -0.9 +/- 1.3, RVED(eff) = 1.2 +/- 1.1, PCW(eff) = 2.1 +/- 2.8, and LVED(eff) = 0.9 +/- 1.6 mm Hg), and filling pressures were highly correlated with airway pressure r = 0.94. On average, group H had higher PCW(eff) and LVED(eff) than L patients by 1.8 and 2.5 mm Hg (P < or = .002), respectively, but after nitrates their responses were identical. CONCLUSION: The relationships between cardiac filling pressure and airway pressure during the Valsalva maneuver are sufficiently reliable to be considered as a new, noninvasive method for establishing the calibration of cardiac pressure sensors in patients with heart failure.

Insulin resistance in idiopathic dilated cardiomyopathy: a possible etiologic link.

OBJECTIVES: This study was designed to quantify the prevalence of abnormal glucose tolerance and insulin resistance in patients with idiopathic dilated cardiomyopathy (IDCM). BACKGROUND: Insulin resistance is an independent risk factor for mortality in patients with heart failure (HF) and is a known risk factor for ischemic cardiomyopathy. Though potential physiologic links between insulin resistance and HF have been hypothesized, the relationship between insulin resistance and IDCM remains unclear. METHODS: A total of 230 consecutive patients from a university HF clinic were screened for IDCM, the absence of diabetes mellitus, and the lack of significant co-morbid conditions. Oral glucose tolerance tests were performed in the 43 patients with IDCM who met these criteria, and their plasma glucose and insulin responses were compared with those of 40 healthy volunteers, matched for age, gender, and body mass index. RESULTS: Plasma glucose responses were higher during the oral glucose tolerance tests in patients with IDCM (p < 0.01), associated with significantly higher plasma insulin concentrations following the oral glucose challenge (p < 0.01). In addition, abnormalities of glucose tolerance were significantly (p < 0.05) more common in patients with IDCM (49% vs. 23%). CONCLUSIONS: Insulin resistance and abnormal glucose tolerance are more prevalent in patients with IDCM and represent potentially reversible metabolic derangements in these individuals.

An unusual cause of dyspnea.

The case of a 71-year-old woman who presented with dyspnea and palpitations is presented. Workup yielded a diagnosis of Fabry's disease, and the patient was referred for therapy. Fabry's disease is a disorder of glycosphingolipid metabolism and has forms that are limited to the myocardium. There is evidence that it has been underrecognized as a cause of cardiac hypertrophy. Because screening can be done with a simple blood test and new treatment options appear promising, we recommend consideration of Fabry's disease in the workup of patients with cardiac hypertrophy.

Pheochromocytoma: cyclic attacks of hypertension alternating with hypotension.

BACKGROUND: A 52-year-old woman was admitted to hospital with recurrent episodes of chest and abdominal pain, dyspnea, palpitations and diaphoresis. Continuous blood pressure recordings revealed rhythmic alternation between episodes of severe hypertension and episodes of hypotension. This cyclic hemodynamic crisis continued for 2 hours, with each cycle lasting around 15 min. INVESTIGATIONS: Physical examination, electrocardiography, chest radiography, continuous intra-arterial pressure monitoring, blood and urine analysis, echocardiography, abdominal CT and 131I miodobenzylguanidine scanning. DIAGNOSIS: Pheochromocytoma--a catecholamine secreting tumor. MANAGEMENT: Intravenous phentolamine and fluids, oral doxazosin and surgical removal of the tumor.

Drug-eluting stenting is superior to bare metal stenting in saphenous vein grafts.

This study compared the outcomes of percutaneous coronary intervention (PCI) of saphenous vein grafts (SVGs) with drug-eluting stents (DES) with bare metal stents (BMS). PCI of degenerated SVG is associated with worse outcomes and high incidence of in-stent restenosis compared with PCI of native coronary arteries. There is a paucity of data on the outcomes of PCI of SVG with DES. Data from 223 consecutive patients who underwent PCI of SVG were imputed into a dedicated clinical database. We assessed the clinical outcomes at a mean follow-up of 9.1+/-2.1 months. A total of 139 patients underwent PCI of SVG with DES and 84 patients with BMS. The mean age of the SVG was 7.6+/-3.8 years in the DES group and 7.7+/-2.8 years in the BMS group (P=0.38). Procedural success was achieved in all patients except for one patient in the BMS group who underwent emergent coronary artery bypass graft surgery for SVG dissection. There were no other in-hospital cardiac events in both groups. There was one cardiac death in the DES group and three deaths in the BMS group (P=0.03). When compared to the BMS, PCI of SVG with DES was associated with a lower incidence of myocardial infarction (4.3% vs. 20.2%; P=0.04) and target vessel revascularization (10.1% vs. 36.9%; P=0.035). When compared with BMS, PCI of SVG with DES was associated with a lower incidence of death, myocardial infarction, and target vessel revascularization.

The effect of variable release kinetics on Paclitaxel efficacy from a drug eluting stent in a porcine model.

AIMS: Paclitaxel is a potent and effective inhibitor of neointimal proliferation after coronary stenting. The Conor stent loaded with Paclitaxel can be programmed with multi-parameter matrix of dose, temporal release profiles and release pathways. The aim of this study was to determine the most efficacious dose and release pattern of Paclitaxel in a porcine model and parallels the PISCES trial. METHODS: 32 farm pigs were implanted with Conor stents loaded with 10 or 30 microg of Paclitaxel with, 10 or 30 day and mural or bidirectional release patterns. Angiographic and histomorphometric analysis was -performed at 30 and 90 days. RESULTS: All doses of Paclitaxel were angiographically superior to control (P < 0.01). At 30 days, intimal thickness was similar between Pisces D4 (30 microg/10 days, bidirectional release), D5 (10 microg/30 day mural) and D6 (30 microg/30 day, mural) with D4 having the lowest intimal thickness (167+/-59 microm). There was a significant increase in the mural injury associated with D4 in comparison to all other doses (P < 0.00001). At 90 days D4 was significantly worse in comparison to Pisces D5 and D6; (P < 0.01) and Pisces D5 and D6 were similar to controls. CONCLUSIONS: 10 day release of Paclitaxel may be too short a period to inhibit neointimal proliferation after coronary stenting, or the rapid release of Paclitaxel may induce chemical injury causing secondary insult to the artery resulting in a rebound increase in intimal thickness at 90 days. These data parallel clinical findings in the PISCES trial.