Long-Term Survival Benefit of Coronary Revascularization in Patients Undergoing Stress Myocardial Perfusion Imaging

Impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic perfusion defect and myocardial flow reserve

PURPOSE

We evaluated the impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic total perfusion defect (ITPD) and myocardial flow reserve (MFR) as assessed by 82Rb positron emission tomography (PET)/computed tomography (CT) imaging.

METHODS

The study included 102 patients referred to 82Rb PET/CT myocardial perfusion imaging before and after coronary revascularization. All patients were followed for the occurrence of cardiovascular events (cardiac death, nonfatal myocardial infarction, repeated revascularization, and heart failure) after the second imaging study.

RESULTS

During a median follow-up of 20 months, 21 events occurred. The clinical characteristics were comparable between patients with and without events. In the overall study population, after revascularization, there was a significant reduction (P < 0.001) of ITPD, while hyperemic myocardial blood flow (MBF) (P < 0.01) and MFR (P < 0.05) significantly improved. Event rate was higher in patients with ITPD (P < 0.005) or MFR (P < 0.001) worsening compared to those with unchanged or improved ITPD or MFR. At Cox univariable analysis, ITPD and MFR worsening resulted in predictors of events (both P < 0.05). Patients with worsening of both ITPD and MFR had the worst event-free survival (log-rank 32.9, P for trend < 0.001).

CONCLUSIONS

In patients with stable CAD, worsening of ITPD and MFR after revascularization procedures is associated with higher risk of cardiovascular events. Follow-up MPI with 82Rb PET/CT may improve risk stratification in patients submitted to coronary revascularization.

Interaction of impaired myocardial flow reserve and extent of myocardial ischemia assessed using 13N-ammonia positron emission tomography imaging on adverse cardiovascular outcomes

BACKGROUND

Myocardial flow reserve (MFR) and the extent of myocardial ischemia identify patients at high risk of major adverse cardiovascular events (MACEs). Associations between positron emission tomography (PET)-assessed extent of ischemia, MFR, and MACEs is unclear.

METHOD

Overall, 640 consecutive patients with suspected or known coronary artery disease undergoing 13N-ammonia myocardial perfusion PET were followed-up for MACEs. Patients were categorized into three groups based on myocardial ischemia severity: Group I (n = 335), minimal (myocardial ischemia < 5%); Group II (n = 150), mild (5-10%); and Group III (n = 155), moderate-to-severe (> 10%).

RESULTS

Cardiovascular death and MACEs occurred in 17 (3%) and 93 (15%) patients, respectively. Following statistical adjustment for confounding factors, impaired MFR (global MFR < 2.0) was revealed as an independent predictor of MACEs in Groups I (hazard ratio [HR], 2.89; 95% confidence interval [CI], 1.48-5.64; P = 0.002) and II (HR, 3.40; 95% CI 1.37-8.41; P = 0.008) but was not significant in Group III (HR, 1.15; 95% CI 0.59-2.26; P = 0.67), with a significant interaction (P < 0.0001) between the extent of myocardial ischemia and MFR.

CONCLUSION

Impaired MFR was significantly associated with increased risk of MACEs in patients with ≤ 10% myocardial ischemia but not with those having > 10% ischemia, allowing a clinically effective risk stratification.

Effect of changes in perfusion defect size during serial stress myocardial perfusion imaging on cardiovascular outcomes in patients treated with primary percutaneous coronary intervention after myocardial infarction

BACKGROUND

We evaluated the prognostic value of changes in perfusion defect size (PDS) on serial MPS in patients treated with primary percutaneous coronary intervention (PCI) after acute myocardial infarction (AMI).

METHODS

We enrolled 112 patients treated with primary PCI after AMI who underwent two stress MPS within 1 month and after 6 months. Improvement in PDS was defined as a reduction ≥5%. Remodeling was defined as an increase in left ventricular (LV) end-diastolic volume index ≥20%. Cardiac events included cardiac death, nonfatal MI, unstable angina, repeated revascularization, and heart failure.

RESULTS

During a median follow-up of 86 months, 22 events occurred. Event rate was higher (P < .01) in patients with worsening of PDS compared to those with unchanged or improved PDS. Moreover, patients with remodeling had a higher (P < .001) event rate compared to those without. At Cox analysis, worsening of PDS and remodeling resulted independent predictors of events (both P < .01). Patients with both worsening of PDS and remodeling had the worst event-free survival (P <.001).

CONCLUSION

In patients treated with primary PCI after AMI, worsening of PDS and remodeling are associated to higher risk of events at long-term follow-up. Gated stress MPS improves risk stratification in these patients.

Atheroma or ischemia: which is more important for managing patients with stable chest pain?

In the evaluation and management of patients with stable chest pain/chronic coronary syndrome, cardiologists need to be able to weigh up the relative merits of managing these patients using either optimal therapy alone or optimal therapy plus revascularization. These decisions rely on an understanding of both the presence and the degree of coronary atheroma and myocardial ischemia, and the impact that these have on patients' symptoms and their prognosis. In this review the authors examine the relative impact of the anatomical and physiological assessment of patients with chronic coronary syndrome and how it can be used to achieve optimal and tailored therapy.

Myocardial stress perfusion scintigraphy for outcome prediction in patients with severe left ventricular systolic dysfunction

Coronary angiography has been recommended in all patients with suspected chronic coronary syndrome and left ventricular ejection fraction (LVEF) ≤35%. The role of ischemia testing, for example, through stress-rest myocardial perfusion scintigraphy (MPS), for risk prediction is not well established.

METHODS

We evaluated 1576 consecutive patients referred to MPS and stratified into 3 LV ejection fraction (LVEF) categories: ≤35%, 36-49%, and ≥ 50%.

RESULTS

Patients with LVEF ≤35% were oldest, most often men, and with the highest likelihood of prior early (elective or urgent) coronary revascularization. They had also the highest values or summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS), as well as the highest frequency of significant coronary artery disease, and a greater number of diseased vessels.

FOLLOW-UP

In this subgroup, 32 cardiovascular death or non-fatal myocardial infarction (MI) (21%), 35 all-cause deaths (22%), and 37 cardiovascular deaths, non-fatal MI, or late revascularizations (27%) were recorded with the shortest survival among all LVEF classes. SRS, SSS, and SDS had very low area under the curve values for the prediction of the 3 endpoints, with very high cut-offs, respectively. SRS and SSS cut-offs predicted a worse outcome in Cox regression models including the number of diseased vessels and early revascularization.

CONCLUSIONS

In patients with LVEF ≤35%, SRS and SSS are less predictive of outcome than in patients with better preserved systolic dysfunction, but their cut-offs retain independent prognostic significance from the number of vessels with significant stenoses and from early revascularization.

Cardiovascular event risk estimated after coronary revascularization and optimal medical therapy: J-ACCESS4 prognostic study

Background

An assessment of cardiac events and survival using quantitative gated myocardial single-photon emission computed tomography (SPECT) (J-ACCESS) associated several risk factors with cardiac events in Japan. The clinical course after revascularization and/or optimal medical therapy (OMT) was followed in patients with coronary artery disease (CAD) at moderate-to-high risk estimated by software incorporating the J-ACCESS risk model. The present study aimed to determine the relevance of changes in estimated risk to outcomes of these therapies.

Methods

This study included 494 patients with possible or definite CAD who underwent initial pharmacological stress ^99mTc-tetrofosmin myocardial perfusion SPECT (MPS) before and eight months after therapy. Major cardiac event risk during 3 years of follow-up was calculated using an equation based on that in the J-ACCESS study. Patients with ≥ 10% cardiac event risk estimated at the first MPS (n = 31) were analyzed and followed up for at least 1 year.

Results

Estimated risk was reduced by ≥ 5% in 14 patients (45%) after therapy. During a follow-up period of 22.1 ± 6.7 months, one patient without such reduction had a major cardiac event. Mean %summed stress scores significantly decreased from baseline to follow-up in patients with and without risk reduction. Left ventricular ejection fraction (LVEF [%]) at rest was significantly increased at the second, compared with the first MPS between patients with, than without risk reduction (57 ± 17 vs. 45 ± 16%, p = 0.001 and 50 ± 11 vs. 49 ± 9%, p = 0.953, respectively).

Conclusions

A reduction in cardiac ischemia and an increase in LVEF by revascularization and/or OMT were necessary to avoid cardiac events among patients with moderate-to-high estimated risk, and changes in event risk were quantifiable.

A New Relational Database Including Clinical Data and Myocardial Perfusion Imaging Findings in Coronary Artery Disease

BACKGROUND

The aim of this study was to test a relational database including clinical data and imaging findings in a large cohort of subjects with suspected or known Coronary Artery Disease (CAD) undergoing stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging.

METHODS

We developed a relational database including clinical and imaging data of 7995 subjects with suspected or known CAD. The software system was implemented by PostgreSQL 9.2, an open source object-relational database, and managed from remote by pgAdmin III. Data were arranged according to a logic of aggregation and stored in a schema with twelve tables. Statistical software was connected to the database directly downloading data from server to local personal computer.

RESULTS

There was no problem or anomaly for database implementation and user connections to the database. The epidemiological analysis performed on data stored in the database demonstrated abnormal SPECT findings in 46% of male subjects and 19% of female subjects. Imaging findings suggest that the use of SPECT imaging in our laboratory is appropriate.

CONCLUSION

The development of a relational database provides a free software tool for the storage and management of data in line with the current standard.

Contemporary Management of Stent Failure: Part One

The occurrence of in-stent restenosis (ISR) still remains a daunting challenge in the current era, despite advancements in coronary intervention technology. The authors explore the underlying pathophysiology and mechanisms behind ISR, and describe how the use of different diagnostic tools helps to best elucidate these. They propose a simplistic algorithm to manage ISR, including a focus on how treatment strategies should be selected and a description of the contemporary technologies available. This article aims to provide a comprehensive outline of ISR that can be translated into evidence-based routine clinical practice, with the aim of providing the best outcomes for patients.

Prognostic impact of reducing myocardial ischemia identified using ECG-gated myocardial perfusion SPECT in Japanese patients with coronary artery disease: J-ACCESS 4 study

AIM

Whether myocardial ischemia identified using myocardial perfusion imaging (MPI) can be an alternative target of coronary revascularization to reduce the incidence of cardiac events remains unclear.

METHODS AND RESULTS

This multicenter, prospective cohort study aimed to clarify the prognostic impact of reducing myocardial ischemia. Among 494 registered patients with possible or definite coronary artery disease (CAD), 298 underwent initial pharmacological stress ^99mTc-tetrofosmin MPI before, and eight months after revascularization or medical therapy, and were followed up for at least one year. Among these, 114 with at least 5% ischemia at initial MPI were investigated. The primary endpoints were cardiac death, non-fatal myocardial infarction and hospitalization for heart failure. Ischemia was reduced ≥5% in 92 patients. Coronary revascularization reduced ischemia (n = 89) more effectively than medical therapy (n = 25). Post-stress cardiac function also improved after coronary revascularization. Ejection fraction significantly improved at stress (61.0% ± 10.7% vs. 65.4% ± 11.3%; p < 0.001) but not at rest (67.1% ± 11.3% vs. 68.3% ± 11.6%; p = 0.144), among patients who underwent revascularization. Rates of coronary revascularization and cardiac events among the 114 patients were significantly higher (13.6%, p = 0.035) and lower (1.1% p = 0.0053), respectively, in patients with, than without ≥5% ischemia reduction. Moreover, patients with complete resolution of ischemia at the time of the second MPI had a significantly better prognosis.

CONCLUSIONS

Reducing ischemia by ≥5% and the complete resolution of ischemia could improve the prognosis of patients with stable CAD.

Correlation between early revascularization and major cardiac events demonstrated by ischemic myocardium in Japanese patients with stable coronary artery disease

BACKGROUND

There is no report on correlation between early revascularization and the occurrence of major cardiac events (MCEs) except severe heart failure in Japanese patients with stable coronary artery disease (CAD). This study aimed to determine whether early revascularization affected the incidence of MCEs in Japanese patients with stable CAD.

METHODS

We retrospectively investigated 3581 stable CAD patients who underwent rest ²⁰¹Tl and stress ^99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography (SPECT) and provided three-year-prognostic data. The endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction, and unstable angina pectoris. On the basis of estimated propensity scores, patients who underwent revascularization within the first 60 days after the SPECT and those who did not were matched in a 1:1 ratio (n=450 per group). We compared MCE rates in relation to the amount of ischemic myocardium detected with the SPECT between the two groups.

RESULTS

The overall incidence of MCEs was not significantly different between the early-revascularization and no-early-revascularization groups (6.7% vs. 8.7%, p=0.2598). Nevertheless, the incidence of MCEs in the patients with ≤5% ischemia was significantly higher in the early-revascularization group than in the no-early-revascularization group (5.8% vs. 0.8%, p=0.0226). In contrast, the incidence of MCEs in the patients with >10% ischemia was significantly lower in the early-revascularization group than in the no-early-revascularization group (7.0% vs. 16.8%, p=0.0036). The incidence of MCEs in the patients with 6-10% ischemia, however, was not significantly different between the early-revascularization and no-early-revascularization groups (6.9% vs. 4.1%, p=0.3235).

CONCLUSIONS

Early revascularization possibly leads to the occurrence of MCEs related to the treatment procedure but may be a therapeutic strategy leading to improvement in prognosis in patients with moderate to severe ischemia.