Prognostic implications of resting distal coronary-to-aortic pressure ratio compared with fractional flow reserve: a 10-year follow-up study after deferral of revascularisation.

INTRODUCTION: The distal coronary-to-aortic pressure ratio (Pd/Pa) is a non-hyperaemic physiological index to assess the functional severity of coronary stenoses. Studies comparing Pd/Pa with fractional flow reserve (FFR) show superior diagnostic efficiency for myocardial ischaemia. Nevertheless, a direct comparison regarding long-term clinical outcomes is still not available. The present observational study compared the prognostic value of Pd/Pa and FFR for major adverse cardiac events (MACE) during a 10-year follow-up period after deferral of revascularisation. METHODS: Between April 1997 and September 2006, we evaluated 154 coronary stenoses (154 patients) in which revascularisation was deferred with intracoronary pressure and flow measurements during the resting and hyperaemic state. Long-term follow-up (median: 11.8 years) was performed to document the occurrence of MACE, defined as a composite of cardiac death, myocardial infarction and target vessel revascularisation. RESULTS: The study population comprised angiographically intermediate coronary stenoses, with a mean diameter stenosis of 53 ± 8%, and intermediate physiological severity with a median FFR of 0.82 (Q1, Q3: 0.76, 0.88). The association of Pd/Pa with long-term MACE was similar to that of FFR [FFR-standardised hazard ratio (sHR): 0.77, 95% confidence interval (CI): 0.61-0.98; Pd/Pa-sHR: 0.80, 95% CI: 0.67-0.96]. In the presence of disagreement between Pd/Pa and FFR, normal Pd/Pa was generally associated with high coronary flow reserve (CFR) and a favourable clinical outcome, whereas abnormal Pd/Pa was generally associated with CFR around the ischaemic cut-point and an impaired clinical outcome, regardless of the accompanying FFR value. CONCLUSION: The present study suggests that Pd/Pa provides at least equivalent prognostic value compared with FFR. When Pd/Pa disagreed with FFR, the baseline index conferred superior prognostic value in this study population.

Acute alterations in glucose homeostasis impact coronary microvascular function in patients presenting with ST-segment elevation myocardial infarction.

BACKGROUND: Microvascular dysfunction in the setting of ST-segment myocardial infarction (STEMI) is thought to be related to stress-related metabolic changes, including acute glucose intolerance. The aim of this study was to assess the relationship between admission glucose levels and microvascular function in non-diabetic STEMI patients. METHODS: 92 consecutive patients with a first anterior-wall STEMI treated with primary percutaneous coronary intervention (PPCI) were enrolled. Blood glucose levels were determined immediately prior to PPCI. After successful PPCI, at 1­week and 6­month follow-up, Doppler flow was measured in culprit and reference coronary arteries to calculate coronary flow velocity reserve (CFVR), baseline (BMR) and hyperaemic (HMR) microvascular resistance. RESULTS: The median admission glucose was 8.3 (7.2-9.6) mmol/l respectively 149.4 mg/dl [129.6-172.8] and was significantly associated with peak troponin T (standardised beta coefficient [std beta] = 0.281; p = 0.043). Multivariate analysis revealed that increasing glucose levels were significantly associated with a decrease in reference vessel CFVR (std beta = -0.313; p = 0.002), dictated by an increase in rest average peak velocity (APV) (std beta = 0.216; p = 0.033), due to a decreasing BMR (std beta = -0.225; p = 0.038) in the acute setting after PPCI. These associations disappeared at follow-up. These associations were not found for the infarct-related artery. CONCLUSION: Elevated admission glucose levels are associated with impaired microvascular function assessed directly after PPCI in first anterior-wall STEMI. This influence of glucose levels is an acute phenomenon and contributes to microvascular dysfunction through alterations in resting flow and baseline microvascular resistance.

Long-term outcomes of a Caucasian cohort presenting with acute coronary syndrome and/or out-of-hospital cardiac arrest caused by coronary spasm.

BACKGROUND: Coronary artery spasm may be the underlying mechanism in up to 10% of cases of acute coronary syndrome (ACS) and sudden cardiac death. Asian individuals exhibit a 3-times greater incidence of spasm than Caucasians; this is likely due to different types of mechanisms. Consequently, solid data is limited about the long-term prognosis in Caucasian patients presenting with ACS and/or out-of-hospital cardiac arrest (OHCA) caused by coronary spasm. METHODS: Between 2002 and 2015, thirty Caucasian patients with coronary artery spasm presenting with ACS (N = 29) and/or OHCA (N = 11) were enrolled in this prospective registry. Follow-up, consisting of regular outpatient visits, was conducted with a mean follow-up period of 7.5 ± 3.3 years. Outcomes included presence of stable angina pectoris, recurrence of ACS, occurrence of implantable cardioverter defibrillator (ICD) shocks and death. RESULTS: The majority of patients (60%) remained asymptomatic during the entire follow-up period. At the end of the follow-up period only 3 patients still experienced stable angina (10%). Only 2 patients (7%) had a recurrent cardiac event, in which the ICD provided appropriate shock therapy. Half of the patients treated with stenting (N = 6), required re-interventions. CONCLUSION: Coronary spasm with ACS and/or OHCA in a Caucasian patient cohort has a relatively benign prognosis in the majority of patients in long-term follow-up, if treated appropriately with medical therapy. Both the role of ICD in OHCA secondary to coronary spasm, and the efficacy of stenting to treat vasospastic angina, warrant further study in large-sized prospective clinical trials.