Background The prevalence of ischemia and its prediction of events are unclear in outpatient diabetic patients in the modern era of intensive medical management. We sought to identify the prevalence of ischemia, subsequent cardiac events, and impact of gender, stress type, and symptom status on these findings in a cohort of outpatient, stable diabetic patients referred for SPECT myocardial perfusion imaging (MPI). Methods and Results The study cohort included 575 consecutive diabetic outpatients who underwent quantitative, gated-SPECT MPI. Clinical information, stress MPI variables, and cardiac events were prospectively collected and analyzed. The study population was at intermediate risk of coronary artery disease (CAD) or had known CAD (40.3%); 29% were asymptomatic at the time of stress testing. Scintigraphic ischemia and significant (≥10%) left ventricular (LV) ischemia were present in 126 (21.9%) and 29 (5.0%), respectively, and <1% had early revascularization. The risk of ischemia was increased >2-fold by male gender (p<0.001) but was not impacted by pharmacologic stress (p=0.15) or presence of symptoms (p=0.89). Over median 4.4 years follow-up, the rate of cardiac death/nonfatal myocardial infarction (MI) was moderate at 2.6%/year (cardiac death 0.8%/year) in the total cohort but was 5.7%/year in those with ischemia (p<0.001). Pharmacologic stress predicted a higher cardiac event rate (p<0.001) but symptoms did not (p=0.55). Conclusions This stable outpatient diabetic SPECT referral cohort had low rates of significant ischemia and early revascularization; an initially-low initial cardiac event rate increased after 2 years. Independent predictors of cardiac death/nonfatal MI were known CAD, pharmacologic stress, and MPI ischemia. Nearly one-third of those with events had a normal MPI, indicating a need for improved risk stratification.

Background Fractional flow reserve (FFR), the hyperemic ratio of distal (Pd) to proximal (Pa) coronary pressure, is used to identify the need for coronary revascularization. Changes in left ventricular end-diastolic pressure (LVEDP) might affect measurements of FFR. Methods and Materials LVEDP was recorded simultaneously with Pd and Pa during conventional FFR measurement as well as during additional infusion of nitroprusside. The relationship between LVEDP, Pa, and FFR was assessed using linear mixed models. Results Prospectively collected data for 528 cardiac cycles from 20 coronary arteries in 17 patients were analyzed. Baseline median Pa, Pd, FFR, and LVEDP were 73 mmHg, 49 mmHg, 0.69, and 18 mmHg, respectively. FFR < 0.80 was present in 14 arteries (70%). With nitroprusside median Pa, Pd, FFR, and LVEDP were 61 mmHg, 42 mmHg, 0.68, and 12 mmHg, respectively. In a multivariable model for the entire population LVEDP was positively associated with FFR such that FFR increased by 0.008 for every 1-mmHg increase in LVEDP (beta = 0.008; P < 0.001), an association that was greater in obstructed arteries with FFR < 0.80 (beta = 0.01; P < 0.001). Pa did not directly affect FFR in the multivariable model, but an interaction between LVEDP and Pa determined that LVEDP’s effect on FFR is greater at lower Pa. Conclusions LVEDP was positively associated with FFR. The association was greater in obstructive disease (FFR < 0.80) and at lower Pa. These findings have implications for the use of FFR to guide revascularization in patients with heart failure. Summary for Annotated Table of Contents The impact of left ventricular diastolic pressure on measurement of fractional flow reserve (FFR) is not well described. We present a hemodynamic study of the issue, concluding that increasing left ventricular diastolic pressure can increase measurements of FFR, particularly in patients with FFR < 0.80 and lower blood pressure.

Patients undergoing ASA had significant and similar improvements in LVOTGs and symptoms regardless of age. Procedural complications were increased in elderly patients, who had numerically but not statistically significantly higher mortality rates.