Pseudo-discordance mimicking low-flow low-gradient aortic stenosis in transcatheter aortic valve replacement patients with severe symptomatic aortic stenosis

Background: While the combination of a small aortic valve area (AVA) and low mean gradient is frequently labeled ‘low-flow low-gradient aortic stenosis (AS)’, there are two potential causes for this finding: underestimation of mean gradient and underestimation of AVA. Methods: In order to investigate the prevalence and causes of discordant echocardiographic findings in symptomatic patients with AS and normal left ventricular (LV) function, we evaluated 72 symptomatic patients with AS and normal LV function by comparing Doppler, invasive, computed tomography (CT) LV outflow tract (LVOT) area, and calcium score (CaSc). Results: Thirty-six patients had discordant echocardiographic findings (mean gradient < 40 mmHg, AV area ≤ 1 cm2). Of those, 19 had discordant invasive measurements (true discordant [TD]) and 17 concordant (false discordant [FD]): In 12 of the FD the mean gradient was > 30 mmHg; technical pitfalls were found in 10 patients (no reliable right parasternal Doppler in 6). LVOT area by echocardiography or CT could not differentiate between concordants and discordants nor between TD and FD (p = NS). CaSc was similar in concordants and FD (p = 0.3), and it was higher in true concordants than in TD (p = 0.005). CaSc positive predictive value for the correct diagnosis of severe AS was 95% for concordants and 93% for discordants. Conclusions: Discordant echocardiographic findings are commonly found in patients with symptomatic AS. Underestimation of the true mean gradient due to technical difficulties is an important cause of these discrepant findings. LVOT area by echocardiography or CT cannot differentiate between TD and FD. In the absence of a reliable and compete multi-window Doppler evaluation, patients should undergo CaSc assessment

Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT

BackgroundEjection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT.MethodsFifty patients (mean age 69 years) undergoing regadenoson same-day rest (8-11 mCi)/stress (32-42 mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started 1 minute after sequential intravenous regadenoson .4 mg and Tc-99m injections, and was composed of five 2 minutes supine gated acquisitions followed by two 4 minutes supine and upright images. Ischemic total perfusion deficit (ITPD) ≥5 % was considered as significant ischemia.ResultsSignificantly lower mean EF reserve was obtained in the 5th and 9th minute after regadenoson bolus in patients with significant ischemia vs patients without (5th minute: -4.2 ± 4.6% vs 1.3 ± 6.6%, P = .006; 9th minute: -2.7 ± 4.8% vs 2.0 ± 6.6%, P = .03).ConclusionsNegative EF reserve obtained between 5th and 9th minutes of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of transient ischemic functional changes with Tc-99m HE-SPECT

Post–ST‐Segment–Elevation Myocardial Infarction Platelet Reactivity Is Associated With the Extent of Microvascular Obstruction and Infarct Size as Determined by Cardiac Magnetic Resonance Imaging

Background Despite optimized medical management and techniques of primary percutaneous coronary intervention, a substantial proportion of patients with ST‐segment–elevation myocardial infarction (STEMI) display significant microvascular damage. Thrombotic microvascular obstruction (MVO) has been implicated in the pathogenesis of microvascular and subsequent myocardial damage attributed to distal embolization and microvascular platelet plugging. However, there are only scarce data regarding the effect of platelet reactivity on MVO. Methods and Results We prospectively evaluated 105 patients in 2 distinct periods (2012–2013 and 2016–2018) who presented with first ST‐segment–elevation myocardial infarction and underwent primary percutaneous coronary intervention. All patients were treated with dual antiplatelet therapy (DAPT). Blood samples were analyzed for platelet reactivity, and cardiac magnetic resonance imaging scans were evaluated for late gadolinium enhancement and MVO. DAPT suboptimal response was defined as hyporesponsiveness to either aspirin or P2Y12 receptor inhibitor agents and demonstrated in 31 patients (29.5%) of the current cohort. Suboptimal platelet response to DAPT was associated with a significantly greater extent of MVO when expressed as a percentage of the left ventricular mass, left ventricular scar, and the number of myocardial left ventricular segments showing MVO (P<0.01 for each). Adjusted multivariable logistic regression model revealed that suboptimal response to DAPT is significantly associated with both greater late gadolinium enhancement (P<0.01) and MVO extent (odds ratio, 3.7 [95% CI, 1.3–10.5]; P=0.01). Patients with a greater extent of MVO were more likely to sustain major adverse cardiovascular events at a 1‐year follow‐up (37% versus 11%; P<0.01). Conclusions In patients undergoing primary percutaneous coronary intervention for ST‐segment–elevation myocardial infarction, platelet reactivity in response to DAPT is a key predictor of the extent of both myocardial and microvascular damage

Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT

BACKGROUND: Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. METHODS: Fifty patients (mean age 69 y) undergoing regadenoson same-day rest (8–11 mCi)/stress (32–42mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started one min after sequential intravenous regadenoson 0.4mg and Tc-99m injection, and was composed of five 2 min supine gated acquisitions followed by two 4 min supine and upright images. Ischemic total perfusion deficit (ITPD) ≥ 5 % was considered as significant ischemia. RESULTS: Significantly lower mean EF reserve was obtained in the 5(th) and 9(th) min after regadenoson bolus in patients with significant ischemia versus patients without (5(th) min: −4.2 ± 4.6% vs. 1.3 ± 6.6%, p = 0.006; 9(th) min: −2.7 ± 4.8% vs. 2.0 ± 6.6%, p = 0.03). CONCLUSIONS: Negative EF reserve obtained between 5(th) and 9(th) min of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of myocardial stunning with Tc-99m HE-SPECT