Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort　- Comparison With Global Studies.

BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

Plasma Renin Activity Predicts the Improvement in Resistant Hypertension after Percutaneous Transluminal Renal Artery Angioplasty.

Objective Percutaneous transluminal renal artery angioplasty (PTRA) has been recommended for the treatment of renovascular resistant hypertension. However, large randomized trials have reported that PTRA did not improve the outcomes compared with optimal medical therapy in patients with renal artery stenosis (RAS). It is important to identify patients with renovascular hypertension who are likely to respond to PTRA. We herein examined whether or not the plasma renin activity (PRA) could predict the improvement in resistant hypertension after PTRA for RAS. Methods and Results A total of 40 patients (mean age: 63±15 years) with unilateral RAS who received PTRA for resistant hypertension were enrolled in this study. Twenty-two (55%) patients experienced a significant reduction in their blood pressure while using few antihypertensive agents at the 3-month follow up. The median PRA was significantly higher in patients using few antihypertensive agents than in those using more [4.2 ng/mL/hr, interquartile range (IQR) 2.6-8.0 vs. 0.8 ng/mL/hr, IQR 0.4-1.7, p<0.001]. To predict the improvement in hypertension after PTRA, a receiver operating characteristic analysis determined the optimal cut-off value of PRA to be 2.4 ng/mL/hr. A multivariate logistic regression analysis showed that higher PRA (>2.4 ng/mL/hr) was an independent predictor of the improvement in hypertension after PTRA (odds ratio: 22.3, 95% confidence interval: 2.17 to 65.6, p<0.01). Conclusion These findings suggest that the evaluation of preoperative PRA may be a useful tool for predicting the improvement in resistant hypertension after PTRA for patients with RAS.

The association between defibrillation shock energy and acute cardiac damage in patients with implantable cardioverter defibrillators.

BACKGROUND: The aim of this study was to establish a minimally invasive defibrillation testing (DT) protocol for patients with implantable cardioverter defibrillators (ICDs). METHODS: Two different energy DTs were performed, immediately after (15 J-DT) and 7 days after (≤10 J-DT) device implantation, in 20 consecutive ICD implantation patients. Cardiac-troponin T (c-TNT) and heart-type fatty acid binding protein (H-FABP) levels were measured before implantation, 2 h after implantation, and 1 day after each DT. For an additional 122 patients with ICD, we retrospectively analyzed 203 DTs immediately and 7 days after device implantation. RESULTS: Serum c-TNT levels were significantly elevated 2 h after 15 J-DT [0.008 (0.004-0.019) vs. 0.053 (0.037-0.068) ng/mL, p<0.001], but not ≤10 J-DT [0.007 (0.004-0.018) ng/mL]. Similarly, serum H-FABP levels were significantly elevated 2 h after 15 J-DT (2.9±1.5 vs. 6.4±3.4 ng/mL, p<0.001), but not ≤10 J-DT (2.7±1.5 ng/mL). The changes in c-TNT and H-FABP levels between baseline and 2 h after DT were significantly greater for 15 J-DT compared with ≤10 J-DT [c-TnT: 0.039 (0.029-0.060) vs. 0 (0-0.003) ng/mL, p<0.001; H-FABP: 3.6±2.8 vs. -0.16±1.1 ng/mL, p<0.001]. The success rates of the initial shocks delivered for ventricular fibrillation were no different between ≤10 J-DT (85% [78/92]) and ≥15 J-DT (92% [103/111]). CONCLUSIONS: Elevated levels of myocardial damage markers such as c-TNT and H-FABP were not found after ≤10 J-DT. In addition, an acceptable success rate was confirmed in ≤10 J-DT.

Difference of clinical course after catheter ablation of atrioventricular nodal reentrant tachycardia between younger and older patients: atrial vulnerability predicts new onset of atrial fibrillation.

BACKGROUND: The aim of this study was to compare the long-term procedural outcomes, the stability of atrioventricular conduction, and the new onset of atrial fibrillation (AF), after ablation of atrioventricular nodal reentrant tachycardia (AVNRT). METHODS AND RESULTS: Consecutive patients with AVNRT (n=109), who underwent slow-pathway ablation, were divided into two groups based on the median age of the studied patients: the younger group aged <55 years and the older group aged ≥55 years. During a mean follow-up period of 60.6 months, the rate of change in the PR interval from before ablation to follow-up was significantly greater in older patients compared with younger patients. However, there was no delayed-onset high-degree AV block during follow-up in either group. No patients in the younger group suffered from persistent AF, whereas persistent AF occurred in 5/54 (9.3%) older patients. Multivariate Cox analysis revealed that atrial vulnerability, with induction of AF during the electrophysiological study, was the only predictor of the development of AF (Hazard ratio: 13.9, 95% confidence interval: 1.62-119.2, p<0.01). CONCLUSION: Slow-pathway ablation of AVNRT is a reliable strategy even in older patients. However, physicians should consider regular long-term follow-up of older patients with atrial vulnerability, in order to assess the subsequent development of AF.

[Prognosis of type A acute aortic dissection treated conservatively].

We examined 58 cases of type A acute aortic dissection treated from 2003 to 2005 in our hospital. Thirty-three patients were treated surgically and 25 patients were treated conservatively. Among the 25 patients treated conservatively, 13 patients had open false lumen, and were eligible for surgical therapy. Surgical therapy was abandoned however, for various reasons (stroke, advanced age, malignancy, renal disease, lung disease, or patient's reject). Thirteen patients (52%) treated conservatively died while only 1 patient (3%) treated surgically died. Patients with thrombosed false lumen had good prognosis while those with open false lumen or ischemic complication had poor prognosis. It is concluded that patients with thrombosed false lumen of type A acute aortic dissection could receive conservative therapy with surgical team's back up and close computed tomography (CT) follow up to detect recanalization and enlargement of the aorta.

Component analysis of HPLC profiles of unique lipoprotein subclass cholesterols for detection of coronary artery disease.

BACKGROUND: Patients with coronary artery disease (CAD) are known to have several lipoprotein abnormalities. We examined plasma cholesterol concentrations of major lipoproteins and their subclasses, using a gel permeation HPLC, to establish an association between a lipoprotein subclass pattern and the presence of CAD. METHODS: We performed a simple and fully automated HPLC, followed by mathematical treatment on chromatograms, for measuring cholesterol concentrations of major lipoproteins and their subclasses in 62 male patients (45 with CAD and 17 controls without CAD) who underwent cardiac catheterization. RESULTS: For major lipoprotein classes, the patient group had a significantly (P<0.05) higher LDL-cholesterol (LDL-C) and lower HDL-cholesterol (HDL-C), but no difference in VLDL-cholesterol (VLDL-C) concentrations. For lipoprotein subclasses, the patient group had a significantly higher small VLDL-C (mean particle diameter of 31.3 nm, P<0.001), small LDL-C (23.0 nm, P<0.05), and very small LDL-C (16.7-20.7 nm, P<0.001), but a significantly lower large HDL-C (12.1 nm, P<0.001) concentrations. Combined variables of "small VLDL-C+small LDL-C+very small LDL-C-large HDL-C" differentiated the patient from the control group more clearly than single-subclass measurements or calculated traditional lipid markers. CONCLUSIONS: These results suggest the usefulness of multiple and simultaneous subclass analysis of proatherogenic and antiatherogenic lipoproteins and indicate that HPLC and its component analysis can be used for easy detection and evaluation of abnormal distribution of lipoprotein subclasses associated with CAD.

Cystatin C, a novel measure of renal function, is an independent predictor of cardiac events in patients with heart failure.

BACKGROUND: Cystatin C, a novel endogenous marker of glomerular filtration rate, has been reported as more sensitive to detect renal insufficiency than creatinine. The purpose of the present study was to examine the clinical significance of serum cystatin C level in patients with mild to moderate heart failure. METHODS AND RESULTS: Serum levels of cystatin C were measured by an enzyme immunoassay in 140 patients with heart failure and 64 control subjects without heart failure. Patients were prospectively followed during a median follow-up period of 480 days, with the end points of cardiac death and progressive heart failure requiring rehospitalization. Serum levels of cystatin C were higher in patients with heart failure than in control subjects (1.14 +/- 0.60 ng/mL versus 0.72 +/- 0.14 ng/mL, P < .001). The Cox multivariate proportional hazard analysis revealed that a change of 1 standard deviation (SD) in cystatin C level was the one of independent predictor for cardiac events (hazard ratio, 1.94; 95% confidence interval, 1.29-6.64; P < .01). The cardiac event rate was markedly higher in patients with elevated cystatin C level (> or =1.0 ng/mL) than in those with normal level (< or =1.0 ng/mL) (38.7% versus 10.3%, P < 0.001). Furthermore in patients with normal creatinine levels (n = 91), the cardiac event rate was similarly higher in patients with elevated cystatin C than in those with normal levels (29.2% versus 7.5%, P = .002). CONCLUSION: Elevation of serum cystatin C, a new marker of renal function, provides promising prognostic information for clinical outcome in patients with mild to moderate heart failure.

Serum heart-type fatty acid binding protein predicts cardiac events in elderly patients with chronic heart failure.

BACKGROUND AND OBJECTIVES: Heart-type fatty acid binding protein (H-FABP) is released into the circulation from the damaged myocardium of patients with severe chronic heart failure. Chronic heart failure is the most frequent cause of death and disability in the elderly. However, there are no data for the prognostic value of H-FABP in the elderly population. This study investigated whether H-FABP can effectively predict the prognosis in elderly patients (> or = 70 years) with chronic heart failure. METHODS: Serum H-FABP levels were measured in 90 chronic heart failure patients > or =70 years old (mean age 77 +/- 4 years, range 70-92 years), and patients were followed-up for 421 +/- 326 days. RESULTS: There were 35 cardiac events (38.9%) including cardiac deaths and readmissions for worsening chronic heart failure. Multivariate analysis with the Cox proportional hazard model showed that H-FABP was the only independent predictor of cardiac events (chi2 = 6.640, p = 0.0100). Kaplan-Meier analysis revealed that H-FABP effectively risk stratified elderly patients with chronic heart failure for cardiac events. CONCLUSIONS: These findings suggest that H-FABP is a reliable marker for prognosis in elderly patients with chronic heart failure.

Prognostic value of elevated circulating heart-type fatty acid binding protein in patients with congestive heart failure.

BACKGROUND: Heart-type fatty acid binding protein (H-FABP) is released into the circulation when the myocardium is injured and is a novel marker for the diagnosis of acute myocardial infarction. The purpose of the present study was to examine the clinical significance of increased serum H-FABP levels in patients with congestive heart failure. METHODS AND RESULTS: Serum levels of H-FABP were measured in 179 patients admitted with congestive heart failure and 20 age-matched normal controls by using a sandwich enzyme-linked immunosorbent assay. Patients were prospectively followed during a mean follow-up period of 20 months with the end points of cardiac death and progressive heart failure requiring rehospitalization. Serum levels of H-FABP were higher in patients with congestive heart failure than in control subjects (5.7 +/- 4.8 ng/mL versus 2.7 +/- 0.8 ng/mL, P < .01) and increased with advancing NYHA class (P < .01). The cardiac event rate was markedly higher in patients with elevated H-FABP levels than in those with normal levels (43% versus 7%, P < .0001). Furthermore, the Cox multivariate proportional hazard analysis revealed that the elevated H-FABP level was the only independent predictor for cardiac events (chi2= 7.397, P < .01). CONCLUSIONS: Elevation of H-FABP indicates latent and ongoing cardiomyocyte damage and identifies patients at high risk for future cardiac events in congestive heart failure.

Dynamic 123I-MIBG SPECT reflects sympathetic nervous integrity and predicts clinical outcome in patients with chronic heart failure.

123I-metaiodobenzylguanidine (123I-MIBG) is useful for assessment of the severity and prognosis of patients with chronic heart failure (CHF). To examine 123I-MIBG kinetics in the early phase soon after tracer injection, we performed dynamic single photon emission computed tomography (SPECT) in 76 patients with CHF and 17 control subjects. The consecutive 15 images of 2 min-dynamic SPECT were acquired for 30 min after injection. From 0 to 4 min, a significant amount of radioactivity existed in the blood pool, thus we calculated washout rate of 123I-MIBG from 4 to 30 min (%WR-E). Patients were followed up with an end-point of cardiac death or re-hospitalization for 16 months (6-30 months). As the NYHA functional class advanced, %WR-E increased (control, NYHA class I, II, and III: 9 +/- 4%, 10 +/- 5%, 12 +/- 5%, and 17 +/- 5%*, respectively, *p < 0.01 vs. all other groups). Significant correlation was found between %WR-E and conventional WR from 30 min to 240 min (r = 0.606, p < 0.0001). %WR-E was positively correlated with left ventricular end-diastolic dimension (r = 0.372, p < 0.01) and was inversely correlated with left ventricular fractional shortening (r = -0.316, p < 0.02). The normal upper limit of %WR-E was defined as mean + 2SD value of 17 control subjects (17.1%). Patients with abnormally rapid %WR-E levels had a higher cardiac event rate than those with normal %WR-E levels (57% vs. 12%, p < 0.0001). These data suggest that washout rate of 123I-MIBG in the early phase from 4 min to 30 min (%WR-E) reflects cardiac sympathetic nervous integrity and is useful to evaluate the severity and prognosis of patients with CHF. The present results indicate a potential role of dynamic SPECT in shortening the 123I-MIBG imaging protocol.

Dynamic 123I-BMIPP single-photon emission computed tomography in patients with congestive heart failure: effect of angiotensin II type-1 receptor blockade.

BACKGROUND: Heart failure is a major and growing public health problem with a high mortality rate. Although recent studies have demonstrated that a variety of metabolic and/or neurohumoral factors are involved in the progression of this syndrome, the precise mechanisms responsible for this complex condition are poorly understood. HYPOTHESIS: To examine 123I-beta-methyl-iodophenylpentadecanoic acid (BMIPP) kinetics in the early phase soon after tracer injection in patients with congestive heart failure (CHF), we performed dynamic single-photon emission computed tomography (SPECT). METHODS: Twenty-six patients with CHF and eight control subjects were examined. The consecutive 15 images of 2-min dynamic SPECT were acquired for 30 min after injection. In the early phase after injection (0-4 min), a significant amount of radioactivity existed in the blood pool. After 6 min, the myocardial 123I-BMIPP image was clear and thus the washout rate of 123I-BMIPP from 6 to 30 min was calculated. RESULTS: The washout rate of 123I-BMIPP from the myocardium was faster in patients with CHF than in the controls (8 +/- 4 vs. -5 +/- 3%, p < 0.01). The washout rate of 123I-BMIPP demonstrated positive correlation with left ventricular (LV) end-diastolic volume index (R = 0.54, p < 0.02) and inverse correlation with LV ejection fraction (R = 0.53, p <0.02). Patients were given the angiotensin II type-1 receptor antagonist candesartan for 6 months, and dynamic SPECT was repeated. The enhanced washout rate of 123I-BMIPP in CHF was reduced after treatment with candesartan (p < 0.05). CONCLUSION: These data suggest that (1) enhanced washout of 123I-BMIPP was observed soon after injection in patients with CHF, (2) the activation of angiotensin II signaling pathway is involved as an intracellular mechanism for enhanced 123I-BMIPP washout in heart failure, and (3) improvement in fatty acid metabolism may represent a new mechanism for beneficial effects of angiotensin II receptor blockade on cardiac function and survival in patients with heart failure. 123I-BMIPP washout in the early phase obtained from dynamic SPECT may be a new marker for evaluating the severity of heart failure and the effects of medical treatment.