First US experience following FDA approval of the ABBOTT vascular bioresorbable vascular scaffold for the treatment of coronary artery disease.

Drug eluting stents are considered the "gold standard" for the percutaneous treatment of coronary artery disease. Recent publications have suggested that a reasonable alternative, in well selected cases, may be the ABSORBTM bioresorbable vascular scaffold (BVS) stent. © 2016 Wiley Periodicals, Inc.

Prognostic value of the Index of Microcirculatory Resistance measured after primary percutaneous coronary intervention.

BACKGROUND: Most methods for assessing microvascular function are not readily available in the cardiac catheterization laboratory. The aim of this study is to determine whether the Index of Microcirculatory Resistance (IMR), measured at the time of primary percutaneous coronary intervention, is predictive of death and rehospitalization for heart failure. METHODS AND RESULTS: IMR was measured immediately after primary percutaneous coronary intervention in 253 patients from 3 institutions with the use of a pressure-temperature sensor wire. The primary end point was the rate of death or rehospitalization for heart failure. The prognostic value of IMR was compared with coronary flow reserve, TIMI myocardial perfusion grade, and clinical variables. The mean IMR was 40.3±32.5. Patients with an IMR >40 had a higher rate of the primary end point at 1 year than patients with an IMR ≤40 (17.1% versus 6.6%; P=0.027). During a median follow-up period of 2.8 years, 13.8% experienced the primary end point and 4.3% died. An IMR >40 was associated with an increased risk of death or rehospitalization for heart failure (hazard ratio [HR], 2.1; P=0.034) and of death alone (HR, 3.95; P=0.028). On multivariable analysis, independent predictors of death or rehospitalization for heart failure included IMR >40 (HR, 2.2; P=0.026), fractional flow reserve ≤0.8 (HR, 3.24; P=0.008), and diabetes mellitus (HR, 4.4; P<0.001). An IMR >40 was the only independent predictor of death alone (HR, 4.3; P=0.02). CONCLUSIONS: An elevated IMR at the time of primary percutaneous coronary intervention predicts poor long-term outcomes.

Peripheral edema due to heart disease: diagnosis and outcome.

BACKGROUND: The purpose of this study was to determine whether baseline physical examination and history are useful in identifying patients with cardiac edema as defined by echocardiography, and to compare survival for patients with cardiac and noncardiac causes of edema. HYPOTHESIS: Physical examination and history data can help to identify patients with edema who have significant cardiac disease. METHODS: We reviewed the medical records of 278 consecutive patients undergoing echocardiography for evaluation of peripheral edema. We classified cardiac edema as the presence of any of the following: left ventricular ejection fraction < 45%, systolic pulmonary artery pressure > 45 mmHg, reduced right ventricular function, enlarged right ventricle, and a dilated inferior vena cava. RESULTS: The mean age of the 243 included patients was 67 +/- 12 years and 92% were male. A cardiac cause of edema was found in 56 (23%). Independent predictors of a cardiac cause of edema included chronic obstructive pulmonary disease (COPD, odds ratio [OR] 1.74, 95% confidence interval [CI] 1.14-2.60) and crackles (OR 1.98, 95% CI 1.26-3.10). The specificity for a cardiac cause of edema was high (91% for COPD, 93% for crackles); however, the sensitivity was quite low (27% for COPD, for 24% crackles). Compared with patients without a cardiac cause of edema, those with a cardiac cause had increased mortality (25 vs. 8% at 2 years, p < 0.01), even after adjustment for other characteristics (hazard ratio 1.55, 95% CI 1.08-2.24). CONCLUSIONS: A cardiac cause of edema is difficult to predict based on history and examination and is associated with high mortality.

Calculation of the index of microcirculatory resistance without coronary wedge pressure measurement in the presence of epicardial stenosis.

OBJECTIVES: This study sought to investigate a novel method to calculate the index of microcirculatory resistance (IMR) in the presence of significant epicardial stenosis without the need for balloon dilation to measure the coronary wedge pressure (P(w)). BACKGROUND: The IMR provides a quantitative measure of coronary microvasculature status. However, in the presence of significant epicardial stenosis, IMR calculation requires incorporation of the coronary fractional flow reserve (FFR(cor)), which requires balloon dilation within the coronary artery for P(w) measurement. METHODS: A method to calculate IMR by estimating FFR(cor) from myocardial FFR (FFR(myo)), which does not require P(w) measurement, was developed from a derivation cohort of 50 patients from a single institution. This method to calculate IMR was then validated in a cohort of 72 patients from 2 other different institutions. Physiology measurements were obtained with a pressure-temperature sensor wire before coronary intervention in both cohorts. RESULTS: From the derivation cohort, a strong linear relationship was found between FFR(cor) and FFR(myo) (FFR(cor) = 1.34 × FFR(myo) - 0.32, r(2) = 0.87, p < 0.001) by regression analysis. With this equation to estimate FFR(cor) in the validation cohort, there was no significant difference between IMR calculated from estimated FFR(cor) and measured FFR(cor) (21.2 ± 12.9 U vs. 20.4 ± 13.6 U, p = 0.161). There was good correlation (r = 0.93, p < 0.001) and agreement by Bland-Altman analysis between calculated and measured IMR. CONCLUSIONS: The FFR(cor), and, by extension, microcirculatory resistance can be derived without the need for P(w). This method enables assessment of coronary microcirculatory status before or without balloon inflation, in the presence of epicardial stenosis.

Coronary microcirculatory resistance is independent of epicardial stenosis.

BACKGROUND: Recent studies show that coronary microcirculatory impairment is an independent predictor of poor outcomes in patients with cardiovascular disease. However, controversy exists over whether microcirculatory resistance, a measure of coronary microcirculatory status, is dependent on epicardial stenosis severity. Previous studies demonstrating that microcirculatory resistance is dependent on epicardial stenosis severity have not accounted for collateral flow in their measurement of microcirculatory resistance. We investigated whether the index of microcirculatory resistance is independent of epicardial stenosis by comparing the index of microcirculatory resistance (IMR) levels in patients before and after percutaneous coronary intervention (PCI). METHODS AND RESULTS: Consecutive patients undergoing elective PCI of the left anterior descending artery were recruited. Patients who developed periprocedural myocardial infarction were excluded. A pressure-temperature sensor wire was used to measure the apparent IMR (IMR(app)), which does not adjust for collateral flow, and the true IMR (IMR(true)), which incorporates wedge pressure measurement to account for collateral flow, before and after PCI. In 43 patients, there was no difference between pre- and post-PCI IMR(true) (mean difference=0.8±11.7, P=0.675). IMR(app) was higher pre-PCI compared with post-PCI (mean difference=10.0±14.5, P<0.001). IMR(app) was higher than IMR(true) (mean difference=9.3±14.2, P<0.001), and the difference between the IMR(app) and IMR(true) became greater with decreasing fractional flow reserve and increasing coronary wedge pressure. Pre-PCI fractional flow reserve correlated modestly with IMR(app) (r=-0.33, P=0.03), but not IMR(true) (r=0.26, P=0.10). CONCLUSIONS: Coronary microcirculatory resistance is independent of functional epicardial stenosis severity when collateral flow is taken into account.

The index of microcirculatory resistance predicts myocardial infarction related to percutaneous coronary intervention.

BACKGROUND: Periprocedural myocardial infarction (MI) occurs in a significant proportion of patients undergoing percutaneous coronary intervention (PCI) and portends poor outcomes. Currently, no clinically applicable method predicts periprocedural MI in the cardiac catheterization laboratory before it occurs. We hypothesized that impaired baseline coronary microcirculatory reserve, which reduces the ability to tolerate ischemic insults, is a risk for periprocedural MI and that the index of microcirculatory resistance (IMR) measured during PCI can predict occurrence of periprocedural MI. METHODS AND RESULTS: Consecutive patients undergoing elective PCI of a single lesion in the left anterior descending coronary artery were recruited. A pressure-temperature sensor wire was used to measure IMR before PCI. Of the 50 patients studied, 10 had periprocedural MI. From binary logistic regression analyses of all clinical, procedural, and physiological parameters, univariable predictors of periprocedural MI were pre-PCI IMR (P=0.003) and the number of stents used (P=0.039). Pre-PCI IMR was the only independent predictor in bivariable regression analyses performed by adjusting for each available covariate one at a time (all P≤0.02). Pre-PCI IMR ≥27 U had 80.0% sensitivity and 85.0% specificity for predicting periprocedural MI (C statistic, 0.80; P=0.003). Pre-PCI IMR ≥27 U was independently associated with a 23-fold risk of developing periprocedural MI (odds ratio, 22.7; 95% CI, 3.8-133.9). CONCLUSIONS: These data suggest that the status of the coronary microcirculation plays a role in determining susceptibility toward periprocedural MI at the time of elective PCI. The IMR can predict subsequent risk of developing myocardial necrosis and may guide adjunctive prevention strategies.