Cardiovascular Testing in the United States during the COVID-19 Pandemic: Volume Recovery and Worldwide Comparison.

Purpose: To characterize the recovery of diagnostic cardiovascular procedure volumes in U.S. and non-U.S. facilities in the year following the initial COVID-19 outbreak. Materials and Methods: The International Atomic Energy Agency (IAEA) coordinated a worldwide study called the IAEA Noninvasive Cardiology Protocols Study of COVID-19 2 (INCAPS COVID 2), collecting data from 669 facilities in 107 countries, including 93 facilities in 34 U.S. states, to determine the impact of the pandemic on diagnostic cardiovascular procedure volumes. Participants reported volumes for each diagnostic imaging modality used at their facility for March 2019 (baseline), April 2020, and April 2021. This secondary analysis of INCAPS COVID 2 evaluated differences in changes in procedure volume between U.S. and non-U.S. facilities and among U.S. regions. Factors associated with return to prepandemic volumes in the United States were also analyzed in a multivariable regression analysis. Results: Reduction in procedure volumes in April 2020 compared with baseline was similar for U.S. and non-U.S. facilities (-66% vs -71%, P = .27). U.S. facilities reported greater return to baseline in April 2021 than did all non-U.S. facilities (4% vs -6%, P = .008), but there was no evidence of a difference when comparing U.S. facilities with non-U.S. high-income country (NUHIC) facilities (4% vs 0%, P = .18). U.S. regional differences in return to baseline were observed between the Midwest (11%), Northeast (9%), South (1%), and West (-7%, P = .03), but no studied factors were significant predictors of 2021 change from prepandemic baseline. Conclusion: The reductions in cardiac testing during the early pandemic have recovered within a year to prepandemic baselines in the United States and NUHICs, while procedure volumes remain depressed in lower-income countries.Keywords: SPECT, Cardiac, Epidemiology, Angiography, CT Angiography, CT, Echocardiography, SPECT/CT, MR Imaging, Radionuclide Studies, COVID-19, Cardiovascular Imaging, Diagnostic Cardiovascular Procedure, Cardiovascular Disease, Cardiac Testing Supplemental material is available for this article. © RSNA, 2023.

Chronological comparison of TAVI and SAVR stratified to surgical risk: a systematic review, meta-analysis, and meta-regression.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has been established as a reasonable alternative to surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis. However, long-term outcomes including valve durability and the need for reintervention are unanswered, especially in younger patients who tend to be low surgical risk. We performed a meta-analysis comparing clinical outcomes after TAVI and SAVR over 5 years stratified to low, intermediate, and high surgical risks. METHODS: We identified propensity score-matched observational studies and randomised controlled trials comparing TAVI and SAVR. Primary outcomes, including all-cause mortality, moderate or severe aortic regurgitation, moderate or severe paravalvular regurgitation, pacemaker placement, and stroke, were extracted. Meta-analyses of outcomes after TAVI compared to SAVR were conducted for different periods of follow-up. Meta-regression was also performed to analyse the correlation of outcomes over time. RESULTS: A total of 36 studies consisting of 7 RCTs and 29 propensity score-matched studies were selected. TAVI was associated with higher all-cause mortality at 4-5 years in patients with low or intermediate surgical risk. Meta-regression time demonstrated an increasing trend in the risk of all-cause mortality after TAVI compared with SAVR. TAVI was generally associated with a higher risk of moderate or severe aortic regurgitation, moderate or severe paravalvular regurgitation, and pacemaker placement. CONCLUSIONS: TAVI demonstrated an increasing trend of all-cause mortality compared with SAVR when evaluated over a long-term follow-up. More long-term data from recent studies using newer-generation valves and state-of-the-art techniques are needed to accurately assign risks.

Transcatheter aortic valve implantation (TAVI) was associated with increased all-cause mortality at longer periods of follow-up irrespective of surgical risk. Aortic regurgitation, paravalvular regurgitation, major vascular complications, and pacemaker placement favoured surgical aortic valve replacement (SAVR) over TAVI. TAVI remained superior to SAVR in major bleeding and renal failure events. Long-term data on newer generation valves and up-to-date implantation techniques may provide better durability and improved outcomes after TAVI.

Impact of change of ischemic burden on the outcomes of ESRD patients awaiting kidney transplantation.

BACKGROUND: In asymptomatic patients with end-stage renal disease (ESRD) wait-listed for kidney transplantation (KT), it is unclear whether a change in ischemic burden on serial surveillance SPECT myocardial perfusion imaging (MPI) impacts outcome. METHODS AND RESULTS: In a retrospective cohort of 700 asymptomatic KT candidates with ≥ 2 sequential SPECT-MPI studies, we defined a significant change in ischemic burden between MPIs as ΔSDS of ≥ 2 points. Patients were followed for mean 19 ± 12 months after MPI2 for cardiac death or myocardial infarction. Between MPIs, 29 (4%) subjects received coronary revascularization which was associated with a greater incidence of reduction in ischemic burden on MPI2 (31% vs. 17%, P = 0.049). Among 514 patients with no ischemia on MPI1 (SDS ≤ 1), 15% had new ischemia on MPI2 which was associated with increased MACE (adjusted HR 1.75; CI 1.02-3.01; P = 0.041). Among 186 patients with ischemia on MPI1 (SDS ≥ 2), 66% had improvement of ischemic burden on MPI2 which was associated with significantly lower MACE (adjusted HR 0.46; CI 0.25-0.82; P = 0.009). There was no significant interaction between coronary revascularization and improvement in ischemic burden impacting outcome (interaction P = 0.845). CONCLUSION: Among KT candidates who underwent serial MPI for CAD surveillance, new ischemia was associated with increased MACE risk. Improvement in ischemic burden was associated with lower MACE risk irrespective of coronary revascularization status.

Left-Sided Prosthetic Valve Dysfunction and Gastrointestinal Bleeding.

Introduction We sought to investigate the association between left-sided prosthetic valve dysfunction and gastrointestinal (GI) bleeding. Methods In a retrospective cohort of patients with left-sided prostheses, we identified those who experienced one or more GI bleeds. The latest or chronologically closest echocardiogram to the GI bleed was analyzed by a blinded investigator for prosthetic valve dysfunction. Results Among 334 unique patients, 166 had aortic prostheses, 127 had mitral prostheses, and 41 had both. A total of 58 (17.4%) subjects had GI bleeding events. Patients in the "GI Bleed" group had higher mean ejection fraction (56±14% vs. 49±15%; P = 0.003) and higher prevalence of hypertension, end-stage renal disease, and liver cirrhosis compared to the "No GI Bleed" group. There was a higher prevalence of moderate or severe prosthetic valve regurgitation in the GI Bleed vs. No GI Bleed group (8.6% vs. 2.2%; P = 0.027). Moderate or severe prosthetic valve regurgitation was independently associated with GI bleeding (odds ratio, 6.18; 95% confidence interval, 1.27-30.05; P = 0.024), after adjusting for ejection fraction, hypertension, end-stage renal disease and liver cirrhosis. Paravalvular regurgitation was associated with a higher incidence of GI bleeding compared to transvalvular regurgitation (35.7% vs. 11.9%; P = 0.044). The prevalence of prosthetic valve stenosis was similar between the GI Bleed and No GI Bleed groups (6.9% vs. 5.8%; P = 0.761). Conclusion In a cohort of patients with predominantly surgically placed prosthetic valves, moderate to severe left-sided prosthetic valve regurgitation was independently associated with GI bleeding.

Prevalence and predictors of Twiddler's syndrome.

BACKGROUND: Twiddler's syndrome is a poorly understood clinical phenomenon when patients either consciously or subconsciously rotate their cardiac device resulting in lead dislodgement. We aimed to determine the true prevalence and risk factors associated with Twiddler's syndrome in a real-world population. METHODS: A retrospective chart review was performed on all patients who underwent cardiac device implantation from January 1st 2017 until Jan 1st 2022. We specifically searched for the terms "Twiddler" or "Twiddler's" imbedded within the text of the medical chart. Demographic and clinical variables were collected from the electronic medical record system. We utilized multivariable logistic regression analysis as well as Kaplan-Meier prediction models to determine independent clinical predictors of Twiddler's syndrome as well as associated mortality, respectively. RESULTS: Twenty one out of 1793 patients (1.2%) were identified as having Twiddler's syndrome after chart review. Independent variables associated with Twiddler's syndrome were female sex (OR 3.76; 95% CI 1.29-10.95), antidepressant medications (OR 3.58; 95% CI 1.07-11.99), and BMI (OR 1.08; 95% CI 1.03-1.31). There was no increased six-month mortality via Kaplan-Meier analysis. CONCLUSION: Our study shows that 1.2% of patients in our real-world population had evidence of Twiddler's syndrome. Independent predictors of Twiddler's syndrome include female sex, antidepressant medications as well as BMI.

Myocardial ischemia in patients with large prior infarction: Clinical decision making and review of literature.

Myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) or positron emission tomography (PET) is a widely used technique for the evaluation of coronary artery disease (CAD). Interpreting physicians rely on regional variations in myocardial radiotracer uptake between rest and stress images to identify hemodynamically significant epicardial coronary artery stenosis. However, interpretation of MPI is very difficult in patients with large infarcts where there is no scintigraphically normal reference myocardium for comparison. In these patients, the stress and rest images appear similar due to balanced ischemia in the non-infarct territory. There are no clear guidelines on how to approach these cases. We present a case of MPI with a large right coronary artery territory (RCA) infarct where the left main (LM) coronary artery territory has no relative comparator and the images looked the same on stress and rest. However, the patient had multiple high-risk ancillary findings including electrocardiographic (ECG) changes with regadenoson, transient ischemic dilatation (TID), large severe inferior infarct, low myocardial blood flow (MBF) and myocardial flow reserve (MFR), but most notably increased right ventricular (RV) uptake on the stress images that was a subtle clue that we were dealing with LM equivalent in non-infarct zone. The coronary angiogram confirmed our findings. Through our case, we provide a comprehensive approach and review of literature on how to approach such challenging encounters.

Network Meta-Analysis Comparing Angiotensin Receptor-Neprilysin Inhibitors, Angiotensin Receptor Blockers, and Angiotensin-Converting Enzyme Inhibitors in Heart Failure With Reduced Ejection Fraction.

The superiority of angiotensin receptor-neprilysin inhibitor (ARNI) over angiotensin-converting enzyme inhibitor (ACE-I) and angiotensin receptor blocker (ARB) has not been reassessed after the publication of recent trials that did not find clinical benefits. Therefore, we performed an updated network meta-analysis comparing the efficacy and safety of ARNI, ACE-I, ARB, and placebo in heart failure with reduced ejection fraction. We included randomized clinical trials that compared ARNI, ARB, ACE-I, and placebo in heart failure with reduced ejection fraction. We extracted prespecified efficacy end points and produced network estimates, p scores, and surface under the cumulative ranking curve scores using frequentist and Bayesian network meta-analysis approaches. A total of 28 randomized controlled trials including 47,407 patients were included. ARNI was associated with lower risk of all-cause mortality (relative risk [RR] 0.81, 95% confidence interval [CI] 0.68 to 0.96), cardiac death (RR 0.79, 95% CI 0.64 to 0.99), and major adverse cardiac events (MACEs; RR 0.83, 95% CI 0.72 to 0.97) but higher risk of hypotension (RR 1.46, 95% CI 1.02 to 2.10) than ARB. ARNI was associated with lower risk of MACE (RR 0.85, 95% CI 0.74 to 0.97), but higher risk of hypotension (RR 1.69, 95% CI 1.27 to 2.24) compared with ACE-I. P scores and surface under the cumulative ranking curve scores demonstrated superiority of ARNI over ARB and ACE-I in all-cause mortality, cardiac death, MACE, and hospitalization for heart failure. In conclusion, ARNI was associated with improved clinical outcomes, except for higher risk of hypotension, compared with ARB and ACE-I.

The prognostic and diagnostic implications of surveillance serial myocardial perfusion imaging in asymptomatic renal transplant candidates.

BACKGROUND: The utility of serial SPECT myocardial perfusion imaging (MPI) for CAD surveillance in asymptomatic ESRD patients awaiting kidney transplantation (KT) is uncertain. METHODS AND RESULTS: We retrospectively investigated 700 asymptomatic KT candidates with ≥ 2 pre-transplant SPECT-MPIs (mean interval, 20 ± 13 months). Worsening MPI was defined as total perfusion deficit increase (ΔTPD) > 5%. High clinical risk was defined as ≥ 3 AHA/ACC KT risk factors. The primary outcome was major adverse cardiac events (MACE) of cardiac death or myocardial infarction. The initial MPI was normal in 462 (66%) subjects. On repeat MPI, ΔTPD > 5% was observed in 82 (12%) subjects, and the incidence increased with increasing time gap between MPIs (P = .006). During a mean follow-up of 16 ± 8 months, there were 119 (17%) MACEs. In the entire cohort, ΔTPD > 5% was not significantly associated with MACE (HR = 1.38; P = .210). ΔTPD > 5% was associated with increased MACE rate among patients with normal initial MPI (HR = 2.30; P = .005), but not among those with abnormal initial MPI (P = .260). There was a significant interaction between ΔTPD > 5% and initial MPI normalcy status in predicting MACE (interaction P = .018), such that the predictive value of ΔTPD is dependent on the initial MPI normalcy. Among subjects with normal initial MPI, ΔTPD > 5% was significantly associated with MACE only if the sum of KT risk factors was ≥ 3 (HR = 2.26; P = .016). Among 123 patients who underwent coronary angiography, ΔTPD > 5% was associated with a higher prevalence of obstructive CAD when the initial MPI was normal and the sum of KT risk factors was ≥ 3. CONCLUSION: Among patients with ESRD waitlisted for KT, new/worsening MPI abnormalities are expected. On serial surveillance, ΔTPD > 5% is associated with MACE and obstructive CAD among those with a normal initial MPI and ≥ 3 AHA/ACC KT risk factors.

Feasibility and safety of laser balloon pulmonary vein isolation in patients with prior left atrial appendage occlusion device implantation.

INTRODUCTION: With the increasing adoption of left atrial appendage occlusion (LAAO) procedures and the eligibility of patients for pulmonary vein isolation (PVI) post device placement, we examined the feasibility and safety of laser balloon (LB) for PVI in patients with prior LAAO. METHODS: We retrospectively examined consecutive patients with paroxysmal or persistent, drug-resistant atrial fibrillation (AF) who underwent LB PVI, after Watchman FLX device implantation at Rush University Medical Center between January 2020 and December 2021. RESULTS: Seven patients (four persistent and three paroxysmal) with a mean age of 64 ± 11 years, predominantly male sex (86%), were included in the study. Two (29%) patients had prior cryoablation PVI with recurrence of AF. The mean CHA2 DS2 VASc is 2.6 ± 0.5 and the mean HAS-BLED score is 3.4 ± 0.8. The mean follow-up duration was 10 ± 7 months. The mean duration between Watchman FLX device implantation and LB PVI was 592 days. Acute first pass left pulmonary vein (PV) isolation was achieved in 100% of the procedures. There were no periprocedural complications such as death, pericardial tamponade or effusion, phrenic nerve injury, PV stenosis, device perforation or embolization, or worsening peri-device leak in any of the patients. None of the patients had AF recurrence after the blanking period. CONCLUSION: LB PVI was safe and effective with 100% acute isolation of left-sided veins in patients with prior LAAO device.

Abbreviated versus Standard Duration of DAPT after PCI: A Systematic Review and Network Meta-analysis.

BACKGROUND: Dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) is typically continued for 6-12 months depending on clinical presentation. Recent studies have evaluated the safety of shorter durations of DAPT across stable and unstable coronary syndrome but are limited by smaller patient pools and varying indications. METHODS: The present study performed a systematic review and network meta-analysis comparing abbreviated (1-3 months) with standard (6-12 months) duration of DAPT. Both conventional and frequentist network meta-analyses with a random-effects model were conducted. RESULTS: Seventeen randomized controlled trials, nine of which included 1-3 months of DAPT, were selected. The risks of any bleeding (RR 0.68, 95% CI 0.54-0.85), major bleeding (RR 0.66, 95% CI 0.50-0.86), and net adverse clinical events (NACE) (RR 0.87, 95% CI 0.76-0.99) were lower with abbreviated (1-3 months) than standard-term (6-12 months) DAPT. No significant differences in the risk of myocardial infarction (RR 1.02, 95% CI 0.87-1.18), definite or probable stent thrombosis (RR 1.11, 95% CI 0.83-1.50), and major adverse cardiac events (MACE) (RR 0.96, 95% CI 0.86-1.06) were observed. Network meta-analysis demonstrated lower risk of any bleeding, major bleeding, and NACE with shorter durations of DAPT compared with 12 months. Risks of definite or probable stent thrombosis, myocardial infarction, and MACE were not significantly different. CONCLUSION: The results support the growing body of evidence that abbreviated duration (1-3 months) of DAPT may be considered to reduce the risk of bleeding without any differences in myocardial infarction, stent thrombosis, or MACE.

Does the "July effect" of new trainees at teaching hospitals impact outcomes for patients hospitalized with heart failure? Real-world analyses of more than half a million US admissions.

Introduction: The "July effect" refers to the potential of adverse clinical outcomes related to the annual turnover of trainees. We investigated whether this impacts inpatient heart failure (HF) outcomes. Methods: Data from all adults (≥18 years) admitted with a primary diagnosis of HF at US teaching hospitals from the 2012-2014 National Inpatient Sample were analyzed. Non-teaching hospital admissions were excluded. The primary outcome was in-hospital mortality. Secondary metrics included hospital length of stay (LOS) and total cost adjusted for inflation. Logistic and linear regression models were used to adjust for confounders. Admissions were classified into 4 quarters (Q1-Q4), based on the academic calendar. Q1 and Q4 were designated to assess the effect of novice (July effect) versus experienced trainees, respectively. Results: There were 699,675 HF admissions during Q1 and Q4 in the study period. Mean age was 71 ± 15 years and 48% were females. There were 20,270 in-hospital deaths, with no difference between Q1 and Q4; crude odds ratio (OR) 1.00, 95% confidence interval (CI) 0.94-1.07, p = 0.95. After risk adjustment, there was no in-hospital mortality difference between Q1 and Q4 admissions; adjusted OR 0.96, 95% CI 0.89-1.03, p = 0.23. There was no difference in hospital LOS or total cost; 5.8 versus 5.8 days, p = 0.66 and $13,755 versus $13,586, p = 0.46, in Q1 and Q4, respectively. Conclusions: In this nationally representative sample, there was no evidence of a "July effect" on inpatient HF outcomes in the US. This suggests that HF patients should not delay seeking care during trainee transitions at teaching hospitals.

Novel oral anticoagulants versus vitamin K antagonists in patients with atrial fibrillation after transcatheter aortic valve replacement: A systematic review and meta-analysis.

BACKGROUND: The efficacy and safety of novel oral anticoagulants (NOACs) compared to the current guideline-recommended vitamin K antagonists (VKAs) in atrial fibrillation (AF) patients undergoing transcatheter aortic valve replacement (TAVR) has not been well established. We pooled evidence from all available studies to assess the risks and benefits of this drug class. METHODS: We queried electronic databases (MEDLINE, Scopus, and Cochrane central) up until January 28th, 2022 for studies comparing NOACs to VKAs in AF patients undergoing TAVR. Results from studies were presented as risk ratios (RR) and pooled using a random-effects model. Subgroup analysis by study design and meta-regression analysis were performed to explore heterogeneity. RESULTS: A total of 12 studies (3 RCTs and 9 observational) containing 12,203 patients (mean age 81.2 years; 50.5% men) were identified and included in the analysis. Pooled analysis revealed no significant difference between NOACs and VKAs in terms of stroke or systemic embolism (RR: 0.78; p = 0.18), major bleeding (RR: 0.84; p = 0.32), intracranial hemorrhage (RR 0.61; p = 0.06), all-cause mortality (RR: 0.69; p = 0.07), and myocardial infarction (RR: 1.60; p = 0.24) at a mean length of follow-up of 15.1 months. RCTs and observational studies did not significantly differ across outcomes on subgroup analysis. Meta-regression analysis found heterogeneity in all-cause mortality to be significantly explained by percentage of males (coefficient: 0.049, p = 0.007), mean age (coefficient: 0.221, p < 0.001), and CHA2DS2-VASc score (coefficient: -1.657, p < 0.001). CONCLUSIONS: This meta-analysis suggests that outcomes with NOACs do not significantly differ compared to VKAs following TAVR in patients with AF.

The prognostic utility of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease: The largest cohort to date.

BACKGROUND: There are limited data on the prognostic utility of regadenoson SPECT myocardial perfusion imaging (MPI) in patients with end-stage renal disease (ESRD). METHODS AND RESULTS: In a single-center, retrospective study, we analyzed consecutive ESRD patients who underwent regadenoson SPECT-MPI. The severity of MPI abnormalities and ischemic burden were determined quantitatively. The primary endpoint was major adverse cardiac events (MACE), defined as the composite of cardiac death or myocardial infarction. Among 1,227 subjects (mean age 54 ± 13 years, 47% men), 60 (5%) MACE were observed during a mean follow-up of 2.5 ± 1.8 years. The presence and severity of MPI abnormalities and ischemic burden were associated with a stepwise increase in MACE risk. Abnormal MPI (SSS ≥ 4) was associated with increased MACE risk, independent and incremental to relevant clinical covariates; adjusted hazard ratio, 1.95; 95% confidence interval, 1.15-3.32; Δχ2 = 5.97; P = .013. Myocardial ischemia (SDS ≥ 2) was associated with a trend towards increased MACE risk; adjusted hazard ratio, 1.63; 95% confidence interval, 0.96-2.77; Δχ2 = 3.12; P = .072. CONCLUSION: In the largest cohort to date, we demonstrated the incremental prognostic value of abnormal MPI in predicting MACE risk in ESRD patients. Given its size, our study provides improved risk estimates in this population compared to previous reports.

The prognostic implications of ST-segment and T-wave abnormalities in patients undergoing regadenoson stress SPECT myocardial perfusion imaging.

BACKGROUND: The prognostic implications of ST-segment and T-wave (ST/T) abnormalities in patients undergoing stress SPECT-myocardial perfusion imaging (MPI) are not well defined. METHODS AND RESULTS: This was a single-center, retrospective cohort study of consecutive patients who underwent regadenoson stress SPECT-MPI. Patients with baseline electrocardiogram (ECG) abnormalities that impede ST/T analysis or those with known coronary artery disease were excluded. Patients were categorized as having primary ST abnormalities, secondary ST/T abnormalities due to ventricular hypertrophy or right bundle branch block, T-wave abnormalities, or normal ECG. The primary outcome was major adverse cardiovascular events (MACE) defined as the composite of cardiac death or myocardial infarction. Among 6,059 subjects, 1912 (32%) had baseline ST/T abnormalities. During a mean follow-up of 2.3 ± 1.9 years, the incidence of MACE was significantly higher among patients with secondary ST/T abnormalities compared to those with normal ECG (HR 2.05; 95% confidence interval [CI], 1.04-4.05; P = 0.039). No significant difference in MACE was observed among patients with primary ST abnormalities (HR 1.64; CI 0.87-3.06; P = 0.124) or T-wave abnormalities (HR 1.15; CI 0.62-2.16; P = 0.658) compared with patients who had normal ECG. Among patients with secondary ST/T changes, abnormal MPI was not associated with a significant increase in MACE rates compared to normal MPI (HR 1.18; CI 0.31-4.58; P = 0.808). However, abnormal MPI was associated with higher MACE rates among patients with primary ST abnormalities (HR 4.50; CI 1.44-14.10; P = 0.005) and T-wave abnormalities (HR 3.74; CI 1.20-11.68; P = 0.015). Similarly, myocardial ischemia on regadenoson stress SPECT-MPI was not associated with a significant increase in MACE rates in patients with secondary ST/T abnormalities (HR 1.45; CI 0.38-5.61; P = 0.588), while it was associated with a higher incidence of MACE in patients with primary ST abnormalities (HR 3.012; CI 0.95-9.53; P = 0.049) and T-wave abnormalities (HR 5.06; CI 1.60-15.96; P = 0.002). CONCLUSION: While patients with secondary ST/T abnormalities had significantly higher MACE risk, abnormal MPI or presence of myocardial ischemia on regadenoson SPECT-MPI in this group does not add prognostic information. Patients with primary ST abnormalities and T-wave abnormalities do not seem to have a significantly higher MACE risk compared to those with normal ECG; however, abnormal MPI or presence of myocardial ischemia, in these groups, correlates with higher MACE rates.

The diagnostic and prognostic value of near-normal perfusion or borderline ischemia on stress myocardial perfusion imaging.

BACKGROUND: Data on the diagnostic and prognostic value of subtle abnormalities on myocardial perfusion imaging (MPI) are limited. METHODS AND RESULTS: In a retrospective single-center cohort of patients who underwent regadenoson SPECT-MPI, near-normal MPI was defined as normal left ventricular ejection fraction (LVEF ≥ 50%) and a summed stress score (SSS) of 1-3 vs SSS = 0 in normal MPI. Borderline ischemia was defined as normal LVEF, SSS = 1-3, and a summed difference score (SDS) of 1 vs SDS = 0 in the absence of ischemia. Coronary angiography data within 6 months from MPI were tabulated. Patients were followed for cardiac death (CD), myocardial infarction (MI), coronary revascularization (CR), and Late CR (LCR) [> 90 days post MPI]. Among 6,802 patients (mean age, 62 ± 13 years; 42% men), followed for a mean of 2.5 ± 2.1 years, 4,398 had normal MPI, 2,404 had near-normal MPI, and 972 had borderline ischemia. Among patients who underwent angiography within 6 months, obstructive (≥ 70% or left main ≥ 50%) CAD was observed at higher rates among subjects with near-normal MPI (33.5% vs 25.5%; P = .049) and those with borderline ischemia (40.5% vs 25.8%; P = .004). During follow-up, 158 (2.3%) CD/MI, 246 (3.6%) CR, and 150 (2.2%) LCR were observed. Near-normal MPI (SSS = 1-3), compared to normal MPI (SSS = 0), was not associated with a significant difference in the risk of the composite endpoint of CD/MI (Hazard ratio [HR], 1.21; 95% confidence interval [CI], .88-1.66; P = .243) or LCR (HR 1.28; CI .93-1.78; P = .130), but was associated with a significant increase in the risk of CR (HR 1.91; CI 1.49-2.46; P < .001). Borderline ischemia (SDS = 1), compared to no ischemia (SDS = 0), was not associated with a significant difference in the risk of CD/MI [HR 1.09; CI .70-1.69; P = .693], but was associated with a significant increase in the risk of CR (HR 5.62; CI 3.08-10.25; P < .001) and LCR (HR 2.98; CI 1.36-6.53; P = .006). CONCLUSION: Near-normal MPI and borderline ischemia on SPECT-MPI provide no significant prognostic information in predicting hard cardiac events but are associated with higher rates of obstructive angiographic CAD and coronary revascularizations.