The Prognostic Value of Vasodilator Myocardial Perfusion Imaging in Octogenarians

Adenosine stress myocardial perfusion imaging in octogenarians: Safety, tolerability, and long-term prognostic implications of hemodynamic response and SPECT-related variables

BACKGROUND

Evaluation of tolerability, safety, and prognostic implications of adenosine stress myocardial perfusion imaging (MPI) in octogenarians.

METHODS

370 octogenarians (49% known coronary artery disease) were studied. Hemodynamic response, MPI-related data, and rest-left ventricular ejection fraction (LVEF) based on echocardiography were registered per patient, and prospective follow-up was performed to document all-cause death (ACD), cardiac death (CD), myocardial infarction (MI), and late revascularization.

RESULTS

No deaths or MIs were observed during adenosine infusion or the short-term post-infusion period. 86% of patients were able to tolerate a 6-minute infusion. All side effects terminated spontaneously after infusion cessation, except for one case of pulmonary oedema. After 9.3 years, there were 124 ACDs, 62 CDs, 16 MIs, and 35 revascularizations. Differences between survival curves of summed stress score (SSS)-based risk groups were significant for all end points (P < .001). SSS and LVEF were independent predictors of all end points (P ≤ .01) and lung uptake of cardiac end points. ΔHR <10 bpm (OR = 1.78, P = .004) and inability to increase HR by >10 bpm and decrease systolic blood pressure by >10 mmHg (OR = 2, P = .02) during adenosine infusion were independent predictors of ACD and CD, respectively. Hemodynamic response variables, SSS, and lung uptake provided incremental prognostic value over pre-test data for ACD and CD.

CONCLUSIONS

In octogenarians, adenosine stress MPI is well tolerated and provides effective long-term risk stratification.

Cardiac imaging in the geriatric population: what do we think we know, and what do we need to learn?

Cardiac imaging plays an important role in coronary artery disease (CAD), congestive heart failure (HF) and valvular heart disease (VHD) in the elderly. Imaging defines the structure and function of the cardiac system, refining the understanding of patients' anatomy and physiology and informing a host of clinical care decisions, including prognosis. Yet there is a paucity of evidence to guide the rational use of many imaging modalities in patients of advanced age, a population with considerable clinical heterogeneity, high prevalence and burden of cardiovascular disease (CVD) and atypical presentations of CVD. This paper discusses important considerations for cardiac imaging for older adults, particularly in regard to CAD, VHD and HF, and then presents domains for future research to produce data that would inform clinical care guidelines, appropriate use criteria and imaging lab protocols to address the unique needs of the fast-growing elderly population.

Predictive value of exercise myocardial perfusion imaging in the Medicare population: the impact of the ability to exercise

BACKGROUND

Although the prognostic value of quantitative single photon emission computed tomography myocardial perfusion imaging (MPI) with exercise and pharmacologic stress is well established, the prognostic and management value in the Medicare age population is less clear.

METHODS

The prospectively populated Cleveland Clinic nuclear cardiology database was used to identify 5,994 consecutive pateints, age >65 years [1,664 (28%) exercise MPI, mean age 72.4±5.1, 74% male], who underwent MPI between January 2004 and January 2008. Clinical baseline variables, post test 90 days revascularization and MPI variables were analyzed. Overall and stratified nonparametric survival estimates were obtained by Kaplan-Meier method. Median follow-up time was 2.4 years. Parametric hazard modeling with bootstrap bagging methods was used to determine prognostic variables predicting mortality.

RESULTS

There was no difference in mortality in patients with an abnormal MPI vs. those with normal MPI. Amongst the patients who underwent exercise MPI, there were 103 (6%) deaths and 121 (8.2%) revascularizations. Only lower exercise capacity (<7 METs) and higher end systolic volume (ESV) predicted mortality. Although a larger amount of ischemia influenced down stream revascularization ischemia, revascularization of patients with an abnormal exercise MPI did not offer a survival benefit (log rank P value=0.01).

CONCLUSIONS

In the a Medicare age population, exercise MPI perfusion variables influenced rates of revascularization but failed to provide incremental significant risk-stratification beyond exercise capacity. Maximum METs achieved appears to be a better predictor of survival.

The clinical value of single photon emission computed tomography myocardial perfusion imaging in cardiac risk stratification of very elderly patients (≥80 years) with suspected coronary artery disease

BACKGROUND

The role of single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) in cardiac evaluation of the very elderly patients is unclear. We investigated the clinical value of SPECT MPI in very elderly patients (≥80 years) with suspected coronary artery disease (CAD) as well as in comparison to younger patients.

METHODS AND RESULTS

A retrospective analysis of prospectively collected data from 8,864 patients [1,093 patients ≥80 years (very elderly), 3,369 patients 65-79 years (elderly), and 4,402 patients 50-64 years (middle-aged)] with suspected CAD who underwent exercise and/or pharmacologic stress testing with SPECT MPI between 1996 and 2005 was performed. Clinical and SPECT MPI characteristics, cardiac event rates, early (≤60 days) cardiac catheterization and revascularization rates of very elderly patients were compared to that of younger patients. Mean follow-up for cardiac events (cardiac death or non-fatal myocardial infarction) was 1.9 ± 0.9 years. Very elderly patients with moderate to severely abnormal SSS had a significantly higher annualized cardiac event rate than those with mildly abnormal or normal study (9.6% vs 3.4% and 2.5% respectively, P < .001). Across all categories of SSS, very elderly patients had a significantly higher cardiac event rate as compared to younger patients (P < .001). Early cardiac catheterization and revascularization referrals in very elderly patients increased as a function of severity of ischemia on SPECT MPI (P < .001), although these referral rates were significantly lower in very elderly patients with mild to moderate and severe ischemia as compared to younger patients (P < .05).

CONCLUSIONS

In very elderly patients (≥80 years) with suspected CAD, SPECT MPI has prognostic and incremental value in the noninvasive cardiovascular assessment for risk stratification and may influence medical decisions.

Third Annual Mario S. Verani, MD, Memorial Lecture: The future of clinical nuclear cardiology

It is a great honor and privilege to present the Third Annual Mario S. Verani, MD, Memorial Lecture. Mario Verani (1943-2001) will be remembered foremost for his major contributions to the field of nuclear cardiology (Figure 1). For instance, he was one of the first investigators to recognize that fixed thallium defects were often not just scar but could be reversed by coronary revascularization. This led to an extensive revision of accepted traditional concepts on the meaning of image patterns. Mario's work on risk stratification by myocardial perfusion and function imaging after acute myocardial infarction was equally pioneering. He also laid out the basic principles for the safe use of adenosine for pharmacologic stress testing. Adenosine is now the preferred procedure all over the world in millions of patients. Dr Verani was a founding member and past president (1996-1997) of the American Society of Nuclear Cardiology (ASNC). The day before he died, he received the ASNC Distinguished Service Award. Personally, I will remember Mario as a very dear friend. We spent many hours together at meetings and gatherings all over the world. I still miss his outgoing personality, his warmth, his humor, and his enthusiasm. Above all, I enjoyed his comfortable friendship. That this friendship extended itself naturally to our wives, Regina and Marjan, made it all the more special. One of the best times we had was during a cardiology meeting in Recife, in the country of his birth, Brazil. I was greatly amused and, at the same time, impressed by the admiration and respect bestowed on him by his fellow Brazilians. One evening, we were going some place in the street on foot. We could not walk down the street without Mario being stopped by one or another Brazilian cardiologist who wanted to speak and consult with him. He was clearly greatly admired and appreciated in his country. I jokingly called him "King of Recife," and the king was holding audience. We arrived rather late where we were going... . I will always cherish the memories of our times together. I am grateful that I could visit Mario at his sickbed on the day before he passed away. He was so fragile and, at the same time, so courageous. I felt sad that there was so much that we could have discussed that we did not. Life seems sometimes full of missed opportunities... .