Myocardial perfusion imaging in patients with unprotected left main disease.

BACKGROUND: The management of patients with unprotected left main (LM) coronary artery disease remains challenging, with recent data casting a shadow of doubt on the safety of percutaneous coronary intervention. We aimed at describing the features of patients undergoing myocardial perfusion imaging (MPI) subsequently found to have LM disease. METHODS: We queried our institutional database for subjects without prior revascularization or myocardial infarction (MI), who had undergone MPI followed by invasive coronary angiography within 6 months, comparing those with evidence of angiographically significant LM disease (i.e. diameter stenosis ≥50%) to those without significant coronary artery disease (CAD), or those with CAD not involving LM. Baseline, stress and imaging features were systematically collected and analyzed, and clinical outcomes (death, myocardial infarction, revascularization) sought. RESULTS: We included a total of 74 patients with LM disease, which were compared with 70 without CAD, and 920 with significant CAD not involving LM. MPI was remarkably safe in all subjects, and significant differences were found for several features, but particularly so for ST change, rate pressure product, and left ventricular ejection fraction (all P<0.05). Most patients with LM disease had moderate or severe ischemia, and the apical, lateral and inferior regions were the most sensitive ones. Clinical outcomes after an average of 35 months were worse in patients with LM disease than in subjects with significant CAD not involving LM, albeit non-significantly, possibly in light of the higher use of coronary artery bypass grafting. CONCLUSIONS: MPI is safe and informative in patients with LM disease, and multidimensional appraisal of MPI results may guide decision-making on top of providing prognostic detail and warranty period.

Noninvasive cardiovascular imaging for myocardial necrosis, viability, stunning and hibernation: evidence from an umbrella review encompassing 12 systematic reviews, 286 studies, and 201,680 patients.

INTRODUCTION: The concomitant presence of myocardial necrosis with myocardial ischemia, stunning or hibernation may complicates appraisal of left ventricular (LV) function and patient management. Several imaging modalities have been proposed for the accurate assessment of myocardial necrosis, viability, stunning and hibernation, with mixed results. We aimed to review the evidence base on myocardial necrosis, stunning and hibernation by conducting an umbrella review (i.e. overview of systematic reviews). EVIDENCE ACQUISITION: We searched PubMed and The Cochrane Library for meta-analyses focusing on the diagnostic, prognostic, or management appraisal of myocardial necrosis, viability, stunning and hibernation. Diagnostic test accuracy, prognostic yield, and clinical outcomes were systematically abstracted from shortlisted reviews. EVIDENCE SYNTHESIS: From an initial set of 6069 citations, 12 systematic reviews were finally included, encompassing 286 studies and 201,680 patients. Cardiac magnetic resonance imaging (CMR) had favorable results in 4 reviews that focused on the diagnosis of myocardial stunning or hibernation in patients followed for 6±4 months after coronary revascularization (sensitivity 96% and specificity 91%). Positron emission tomography (PET), single photon emission tomography (SPECT) and CMR in 6 meta-analyses had each a significant and independent prognostic role for the prediction of fatal and non-fatal cardiovascular events in patients with follow-up of 2.8±1.7 years. Finally, 2 reviews with 2.3±1.1 years of follow-up showed moderate quality evidence in favor of coronary revascularization in patients with objective signs of myocardial viability. CONCLUSIONS: The appraisal of myocardial necrosis and residual viability remains a cornerstone of the modern management of patients with CAD. Current imaging modalities (echocardiography, PET, SPECT and CMR) are widely used. Further trials using contemporary methods are warranted to further clarify the impact of viability assessment on patient management, and the cumulative risk of morbidity and mortality.

Comparative analysis between myocardial perfusion reserve and maximal ischemia score at single photon emission computed tomography with new-generation cadmium-zinc-telluride cameras.

BACKGROUND: Whether estimates of myocardial perfusion reserve (MPR) stemming from new-generation cadmium-zinc-telluride (CZT) cameras are accurate remains unclear. METHODS: We queried our institutional database for patients undergoing MPR with CZT cameras. The primary goal was appraising the incremental diagnostic yield of MPR on top or at odds of maximal ischemia score (MIS). RESULTS: A total of 66 subjects were included. When distinguishing patients according to normal vs abnormal MPR (cut-off 2.1 mL/min/g) and normal vs abnormal MIS, 4 groups could be identified: 12 (18.1%) individuals with normal MPR and MIS, 12 (18.1%) with normal MPR and abnormal MIS, 16 (24.2%) with abnormal MPR and normal MIS, and 26 (39.4%) with abnormal MPR and MIS. MIS was significantly associated with several baseline features, whereas MPR did not. There was no significant association between MPR and MIS, nor with regional perfusion. Clinical outcomes were uncommon and not significantly associated with MPR or MIS, whereas angiographically significant coronary artery disease (CAD) was associated solely with MIS (P < 0.05), and not with MPR. CONCLUSIONS: There is limited agreement between CZT-derived MPR and baseline risk, perfusion and angiography results. Whether such discrepancies may still prove incrementally beneficial for the diagnosis or prognosis of CAD remains unclear.

Oral antiplatelet therapy in the elderly undergoing percutaneous coronary intervention: an umbrella review.

Percutaneous coronary intervention has become a mainstay in the management of coronary artery disease. While initially advanced age was considered a relative contraindication to invasive management of coronary artery disease, current cardiovascular practice stands solidly on an early invasive approach for elderly patients, typically based on radial access and drug-eluting stent implantation. Since the advent of coronary stents, oral antiplatelet therapy has proved crucial to maximize the benefits and minimize the risks of stenting, and this holds even truer in older patients rather than in younger ones. Indeed, the elderly is typically at higher risk of thrombotic events as well as bleeding complications, and thus careful decision making must be exercised to prescribe the most appropriate antiplatelet regimen. We thus conducted an umbrella review with scoping purposes on oral antiplatelet therapy in elderly patients undergoing percutaneous coronary intervention, retrieving 8 pertinent systematic reviews. We found that, while several drugs are available, ranging from aspirin to cilostazol, clopidogrel, dipyridamole, prasugrel, ticagrelor, and ticlopidine, most commonly a dual antiplatelet therapy comprising aspirin and a P2Y12 inhibitor is recommended, with subtle adjustments for pretreatment, loading, dose, duration, escalation or de-escalation, with the potential adjunct in selected patients of novel oral anticoagulants. Indeed, a flexible and individualized approach to oral antiplatelet therapy in elderly patients undergoing percutaneous coronary intervention is paramount, factoring patient features (exploiting thrombotic, bleeding and frailty scores), triage (including when appropriate non-invasive assessment of anatomic and functional significance of coronary artery disease), angiographic and other invasive imaging features, interventional technique, stent choice, rehabilitation, and secondary prevention.

Umbrella review and multivariate meta-analysis of diagnostic test accuracy studies on hybrid non-invasive imaging for coronary artery disease.

BACKGROUND: The diagnosis of coronary artery disease (CAD) remains challenging. It is uncertain whether hybrid imaging can improve diagnostic accuracy for CAD. METHODS: This is a systematic review and multivariate meta-analysis. We searched PubMed and The Cochrane Library for recent (≥ 2010) systematic reviews of diagnostic test accuracy studies on non-invasive imaging for CAD. Study-level data were extracted from them, and pooled with pairwise and multivariate meta-analytic methods, using invasive coronary angiography (ICA) or invasive fractional flow reserve (FFR) as reference standards, focusing on sensitivity and specificity. RESULTS: Details from 661 original studies (71,823 patients) were pooled. Pairwise meta-analysis using ICA as reference showed that anatomic imaging was associated with the best diagnostic accuracy (sensitivity = 0.95 [95% confidence interval 0.94-0.96], specificity = 0.83 [0.81-0.85]), whereas using FFR as reference identified hybrid imaging as the best test (sensitivity = 0.87 [0.83-0.90], specificity = 0.82 [0.76-0.87]). Multivariate meta-analysis confirmed the superiority of anatomic imaging using ICA as reference (sensitivity = 0.96, specificity = 0.83), and hybrid imaging using FFR as reference (sensitivity = 0.88 [0.86-0.91], specificity = 0.82 [0.77-0.87]). CONCLUSIONS: Non-invasive hybrid imaging tests appear superior to anatomic or functional only tests to diagnose ischemia-provoking coronary lesions, whereas anatomic imaging is best to diagnose and/or rule out angiographically significant CAD. SYSTEMATIC REVIEW REGISTRATION: PROSPERO Registry Number CRD42018088528.

Hybrid anatomo-functional imaging of coronary artery disease: Beneficial irrespective of its core components.

Coronary artery disease (CAD) is the most common and important cause of ischemic heart disease, with major implications on global morbidity and mortality. Non-invasive testing is crucial in the diagnostic and prognostic work-up of patients with or at risk of CAD, and also to guide decision making in terms of pharmacologic and revascularization therapy. The traditional paradigm is to view anatomic (i.e., coronary computed tomography) and functional imaging (e.g., myocardial perfusion scintigraphy) tests as opposing alternatives. Such approach is too reductionist and does not capitalize on the strengths of each type of test while risking to overlook the inherent limitations. The combination of anatomic and functional tests in a logic of hybrid imaging holds the promise of overcoming the limitations inherent to anatomic and functional testing, enabling more accurate diagnosis, prognosis, and guidance for revascularization in patients with CAD.

Impact of specific coronary lesions on regional ischemia at single photon emission computed tomography.

AIMS: Prior studies using stress myocardial perfusion imaging (MPI), which examined the association between obstructive epicardial coronary disease and presence of myocardial ischemia did not provide a detailed assessment on a regional level. We examined this relationship in a large population of patients in whom the coronary anatomy was defined by invasive coronary angiography. METHODS: We retrospectively extracted details on individuals undergoing MPI with single photon emission computed tomography (SPECT) who had coronary angiography within 12 months. A 17-segment model for native coronary anatomy and a 7-region model for myocardial perfusion were used with a dedicated matching algorithm. RESULTS: A total of 2564 patients were included, yielding a total of 6279 stenoses matched with 17 948 myocardial regions. From such a cohort, 151 (5.9%) patients had normal perfusion, 1878 (73.2%) had myocardial ischemia (reversible defects), 260 (10.1%) had myocardial necrosis (scar or fixed defects), and 275 (10.7%) had ischemia and necrosis. At per-patient analysis, significant angiographic disease was more common in the ischemic group (prevalence between 69.6 and 80.0%) than other groups. At per-region analysis, abnormal perfusion in the coronary-specific regions varied depending on location of stenosis; it was 96% for left main disease, 81% for proximal left anterior descending disease, 85% for proximal left circumflex disease, and 82% for proximal right coronary artery disease and <60% for posterior descending artery disease. CONCLUSION: The correlation between significant coronary stenosis and presence of corresponding regional perfusion abnormality depends on the location of the lesion and the corresponding myocardial region.

Prognostic accuracy of myocardial perfusion imaging in octogenarians.

BACKGROUND: Myocardial perfusion imaging (MPI) has an established role in the work-up of coronary artery disease (CAD), but its comparative accuracy is debated in elderly patients. We examined a large administrative database to appraise the performance of MPI in octogenarians. METHODS: Our institutional database was queried for patients undergoing MPI without recent coronary revascularization or myocardial infarction (MI). We compared baseline, procedural, diagnostic, and prognostic features in patients aged < 80 vs ≥ 80 years with bivariate and propensity-adjusted analyses. RESULTS: From 13,254 patients, 12,737 (96.1%) were < 80 years old and 517 (3.9%) ≥ 80 years. Octogenarians were less likely to undergo exercise testing, had more severe and extensive myocardial ischemia (all P < 0.001), whereas CAD was more prevalent and diffuse in them (P = 0.012), and major adverse cardiac events more common during follow-up (P = 0.009). Diagnostic accuracy of MPI was similar or higher in octogenarians than in younger patients (e.g., sensitivity for three-vessel disease 92% in octogenarians vs 91% in younger patients), as was prognostic accuracy. Using propensity-matched analyses, MPI again yielded satisfactory prognostic accuracy in octogenarians. CONCLUSIONS: Use of MPI in octogenarians is associated with similar or better prognostic accuracy than in younger subjects.

Temporal Trends in the Prevalence, Severity, and Localization of Myocardial Ischemia and Necrosis at Myocardial Perfusion Imaging After Myocardial Infarction.

The definition, presentation, and management of myocardial infarction (MI) have changed substantially in the last decade. Whether these changes have impacted on the presence, severity, and localization of necrosis at myocardial perfusion imaging (MPI) has not been appraised to date. Subjects undergoing MPI and reporting a history of clinical MI were shortlisted. We focused on the presence, severity, and localization of necrosis at MPI with a retrospective single-center analysis. A total of 10,476 patients were included, distinguishing 5 groups according to the period in which myocardial perfusion scintigraphy had been performed (2004 to 2005, 2006 to 2007, 2008 to 2009, 2010 to 2011, 2012 to 2013). Trend analysis showed over time a significant worsening in baseline features (e.g., age, diabetes mellitus, and Q waves at electrocardiogram), whereas medical therapy and revascularization were offered with increasing frequency. Over the years, there was also a lower prevalence of normal MPI (from 16.8% to 13.6%) and ischemic MPI (from 35.6% to 32.8%), and a higher prevalence of ischemic and necrotic MPI (from 12.0% to 12.7%) or solely necrotic MPI (from 35.7% to 40.9%, p <0.001). Yet the prevalence of severe ischemia decreased over time from 11.4% to 2.0%, with a similar trend for moderate ischemia (from 15.9% to 11.8%, p <0.001). Similarly sobering results were wound for the prevalence of severe necrosis (from 19.8% to 8.2%) and moderate necrosis (from 8.5% to 7.8%, p = 0.028). These trends were largely confirmed at regional level and after propensity score matching. In conclusion, the outlook of stable patients with previous MI has substantially improved in the last decade, with a decrease in the severity of residual myocardial ischemia and necrosis, despite an apparent worsening in baseline features.

Impact of coronary revascularization on the clinical and scintigraphic outlook of patients with myocardial ischemia.

AIMS: The impact of coronary revascularization on outcomes and ischemic burden among patients with objective proof of ischemia is not yet established. We appraised the impact of revascularization on outcomes and residual ischemia in patients with objective evidence of ischemia at myocardial perfusion scintigraphy (MPS). METHODS: We queried our database for stable patients with myocardial ischemia at MPS, excluding those with prior myocardial infarction, systolic dysfunction, or cardiomyopathy. The impact of revascularization (defined as revascularization as first follow-up event) on outcomes and changes in myocardial ischemia at repeat MPS was appraised with propensity-matched analyses. RESULTS: From 6195 patients, propensity matching yielded 1262 pairs of patients undergoing revascularization versus not undergoing revascularization. After 35.2 ±â€Š23.9 months, revascularization was associated with lower risks of cardiac death [2 (0.2%) versus 10 (0.8%) in those not revascularized, P = 0.038] and of the composite of cardiac death or myocardial infarction [17 (1.3%) versus 37 (2.9%), P = 0.007]. In addition, revascularization was associated with a higher rate of improvement in ischemia degree after 28.1 ±â€Š20.7 months of follow-up (P < 0.001), with 257 (69.3%) patients with moderate or severe ischemia at baseline MPS improving after revascularization versus 136 (42.0%) in the nonrevascularization group. Conversely, revascularization did not prove impactful on follow-up MPS in patients with only minimal or mild ischemia at baseline MPS (P < 0.001). CONCLUSION: In a large series of patients with objective evidence of myocardial ischemia at MPS, especially when moderate or severe, revascularization was associated with a better clinical prognosis and a lower ischemic burden at repeat MPS.