Invasive Assessment of Microvascular Resistance in Hypertrophic Cardiomyopathy With Echocardiographic Correlates.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is often associated with ischaemia despite lack of focal epicardial coronary stenosis. Our aim was to assess invasive coronary microvascular circulation and correlate findings with echocardiography. METHODS: We prospectively enrolled patients with HCM and controls who were referred for diagnostic coronary angiography. A pressure-temperature sensor coronary guidewire was used with intracoronary injections of room-temperature saline to measure mean coronary transit time during rest and hyperaemia induced with intravenous adenosine. The index of microvascular resistance (IMR) was calculated. Left ventricular mass was calculated during echocardiographic studies. RESULTS: Patients with HCM (n=12) and controls (n=7), had similar demographics. Left ventricular ejection fraction was higher in HCM (76.7%±11.0% vs 55.0%±15.9%, p=0.003). IMR was non-significantly higher in HCM (21.7±10.2 vs 15.3±4.8, p=0.16). Only patients with HCM had abnormal IMR (>25). Coronary flow reserve was non-significantly higher in HCM (2.7±1.6 vs 2.1±1.2, p=0.34). IMR correlated with left ventricular mass in hypertrophic cardiomyopathy subjects (Pearson r=0.68, p=0.02). CONCLUSIONS: Microvascular dysfunction as assessed by IMR may be abnormal in HCM and is correlated with left ventricular mass.

Short Durations of Radial Hemostatic Device After Diagnostic Transradial Cardiac Catheterization: The PRACTICAL-2 Randomized Trial.

BACKGROUND: Radial artery occlusion (RAO) is the most common complication following transradial approach (TRA) for cardiac catheterisation. Our aim was to assess if decreasing radial hemostatic device (RHD) time reduces the risk of RAO among individuals receiving small sheath sizes with no adjunctive heparin. METHODS: We randomised 450 individuals undergoing diagnostic cardiac catheterization via TRA to 3 durations of RHD time: 10, 20, or 30 minutes. After these time periods, the RHD was gradually released over 20 minutes. The primary efficacy end point was forearm hematoma grade ≥ 2 (5-10 cm) and the primary safety end point was RAO (as determined by Doppler ultrasound) 1 hour after RHD removal (before discharge). RESULTS: The mean age was 66 years and 64% were male. Five-French sheaths were used in all patients. Hematoma grade ≥ 2 occurred in only 1 patient, who was in the 20-minute group (P = 0.39). RAO occurred in 6.7% of patients in the 10-minute group, 10.7% in the 20-minute group and 6% in the 30-minute group (P = 0.26). CONCLUSIONS: Among patients receiving small-caliber sheaths without adjunctive heparin, the incidence of forearm hematoma and RAO are low. Shorter durations of RHD time did not further reduce the risk of these complications.

Endothelial Dysfunction Is Not Associated With Spontaneous Coronary Artery Dissection.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is an important cause of acute coronary syndrome, yet its pathophysiology is only partially understood. We sought to assess the association between endothelial dysfunction (ED) and SCAD. METHODS: We prospectively assessed patients presenting with acute coronary syndrome who were diagnosed with SCAD. The control arm had established coronary artery atherosclerotic disease (AD) according to previous coronary angiography. ED was assessed using the EndoPAT 2000 while patients returned to their steady state condition. A total of 16 patients with SCAD and 66 patients with AD were included. RESULTS: Microvascular reactivity as assessed with the EndoPAT was significantly worse in the AD group compared to the SCAD group. The median RHI in the AD group was 1.76 (IQR 1.52, 2.2) vs. a median RHI of 2.08 (IQR 1.73, 2.79) in the SCAD group (p < 0.05). While the RHI values in half of the AD group (33 patients; 50%) were below the cut-off of 1.67 only one patient had an RHI below this cut-off in the SCAD group. CONCLUSIONS: Patients with SCAD were not found to have ED and it is therefore unlikely that ED takes part in SCAD formation.