Outcome of patients with adenosine-induced ST-segment depression but with normal perfusion on tomographic imaging

Abnormal vasodilator stress electrocardiogram with normal myocardial perfusion: Clinical decision-making and review of literature

Ischemic electrocardiographic (ECG) changes during vasodilator stress testing in the presence of abnormal myocardial perfusion imaging (MPI) are associated with more severe coronary artery disease (CAD). However, significance of ECG changes during vasodilator stress test with normal MPI has been controversial. Here, we discuss two cases of significant ischemic ECG changes with vasodilator stress and normal MPI, whose subsequent workup revealed severe obstructive CAD. We also review the available literature on the occurrence and mechanism of these discrepant findings and propose recommendations for management.

Prognostic significance of ischemic electrocardiographic changes with regadenoson stress myocardial perfusion imaging

BACKGROUND

In patients undergoing regadenoson SPECT myocardial perfusion imaging (MPI), the prognostic value of ischemic ST-segment depression (ST↓) and the optimal ST↓ threshold have not been studied.

METHODS

A retrospective cohort study of consecutive patients referred for regadenoson stress MPI was conducted. Patients with uninterpretable ECG were excluded. Two diagnostic thresholds of horizontal or downsloping ST↓ were studied, ≥ 0.5 mm and ≥ 1.0 mm. The primary endpoint was the composite major adverse cardiac events (MACE) of cardiac death, myocardial infarction, or coronary revascularization.

RESULTS

Among 8615 subjects (mean age 62 ± 13 years; 55% women), 89 (1.0%) had ST↓ ≥ 1.0 mm and 133 (1.5%) had ST↓ ≥ 0.5 mm. Regadenoson-induced ST↓ was more common in women (P < .001). Mean follow-up was 2.5 ± 2.2 years. After multivariate adjustment, ST↓ ≥ 1.0 mm was associated with a non-significant increase in MACE risk (P = .069), irrespective to whether MPI was abnormal (P = .162) or normal (P = .214). Ischemic ST↓ ≥ 0.5 mm was independently associated with MACE in the entire cohort (HR 2.14; CI 1.38-3.32; P = .001), whether MPI is normal (HR 2.07; CI 1.07-4.04; P = .032) or abnormal (HR 2.24; CI 1.23-4.00; P = .007), after adjusting for clinical and imaging covariates. An ST↓ threshold of ≥ 0.5 mm provided greater incremental prognostic value beyond clinical and imaging parameters (Δχ2 = 12.78; P < .001) than ≥ 1.0 mm threshold (Δχ2 = 3.72; P = .093).

CONCLUSION

Regadenoson-induced ischemic ST↓ is more common in women and it provides a modest independent prognostic value beyond MPI and clinical parameters. ST↓ ≥ 0.5 mm is a better threshold than ≥ 1.0 mm to define ECG evidence for regadenoson-induced myocardial ischemia.

Prevalence of ECG changes during adenosine stress and its association with perfusion defect on myocardial perfusion scintigraphy

OBJECTIVE

Myocardial perfusion scintigraphy (MPS) is a valuable, noninvasive imaging modality in the evaluation of patients with coronary artery disease. Adenosine stress may occasionally be associated with ECG changes. This study evaluated the strength of association between adenosine stress-related ECG changes and perfusion defects on Tc-MPS.

PATIENTS AND METHODS

117 (mean age: 61.25±9.27 years; sex: men 87, women 30) patients with known/suspected coronary artery disease underwent adenosine stress MPS. ECG was monitored continuously during adenosine stress for ST-depression. On the basis of the summed difference score, reversible perfusion defects were categorized as follows: normal: less than 4, mild: 4-8, moderate: 9-13, and severe: more than 13.

RESULTS

ST-depression was observed in 27/117 (23.1%) and reversible perfusion defects were observed in 18/27 (66.66%) patients. 2/27, 6/27, and 10/27 patients had mild, moderate, and severe ischemia, respectively. 9/27 patients had normal perfusion. ECG changes and perfusion defects showed a moderate strength of association (correlation coefficient r=0.35, P=0.006). The sensitivity, specificity, positive predictive value, and negative predictive value of ECG findings for prediction of ischemia were 35.29, 86.36, 67.67, and 63.33%, respectively.

CONCLUSION

ECG changes during adenosine stress are not uncommon. It shows a moderate strength of association with reversible perfusion defects. ECG changes during adenosine merit critical evaluation of MPS findings.

The prognostic value of non-perfusion variables obtained during vasodilator stress myocardial perfusion imaging

Myocardial perfusion imaging (MPI) is an established diagnostic test that provides useful prognostic data in patients with known or suspected coronary artery disease. In more than half of the patients referred for stress testing, vasodilator stress is used in lieu of exercise. Unlike exercise, vasodilator stress does not provide information on exercise and functional capacity, heart rate recovery, and chronotropy, and ECG changes are less frequent. These non-perfusion data provide important prognostic and patient management information. Further, event rates in patients undergoing vasodilator MPI are higher than in those undergoing exercise MPI and even in those with normal images probably due to higher pretest risk. However, there are a number of non-perfusion variables that are obtained during vasodilator stress testing, which have prognostic relevance but their use has not been well emphasized. The purpose of this review is to summarize the prognostic values of these non-perfusion data obtained during vasodilator MPI.

Review of Cardiovascular Imaging in the Journal of Nuclear Cardiology in 2015-Part 2 of 2: Myocardial perfusion imaging

In 2015, the Journal of Nuclear Cardiology (®) published many high-quality articles. In this series, we will summarize key articles that have appeared in the Journal last year to provide for the interested reader a quick review of the advancements that have recently occurred in the field. In the first article of this 2-part series, we concentrated on publications dealing with plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance. This review will focus on myocardial perfusion imaging summarizing advances in the field including in diagnosis, prognosis, and appropriate use.

Diagnostic and prognostic significance of ischemic electrocardiographic changes with regadenoson-stress myocardial perfusion imaging

BACKGROUND

The diagnostic and prognostic value of regadenoson-induced ST-segment depression (ST↓) is not defined. Due to the low incidence of ST↓ ≥1.0 mm with vasodilator stress, a lower threshold to define ischemic ECG response may provide improved clinical utility.

METHODS

We conducted a retrospective cohort study of patients who underwent regadenoson-stress SPECT myocardial perfusion imaging (MPI) followed by coronary angiography within 6 months. Ischemic ST↓ was defined as ≥0.5 mm. The prevalence of angiographically severe coronary artery disease (CAD) and the rates of major adverse cardiac events (MACE) including cardiac death, myocardial infarction, and coronary revascularization were determined.

RESULTS

In a diagnostic cohort of 629 subjects, 117 (18.6%) had ST↓ ≥0.5 mm. Severe CAD was more prevalent in the ST↓ ≥0.5 vs ST <0.5 group (13.7% vs 5.3%, P = .001). Among patients with normal MPI (n = 229), the prevalence of severe CAD was higher in the ST↓ ≥0.5 group (8.2% vs 2.2%, P = .04). Adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was independently predictive of severe CAD [odds ratio = 3.37, 95% confidence interval (CI) = 1.67-6.83, P = .001], and provided incremental diagnostic value (Chi square increment = 10.3, P = .001). In an outcome cohort of 748 subjects, after adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was associated with increased MACE rate in the entire cohort [hazard ratio = 1.41, CI 1.01-1.96, P = .04] and in the subgroup of patients with normal MPI [hazard ratio = 2.2, CI 1.11-4.39, P = .02], and provided incremental prognostic value (Chi square increment = 3.9, P = .049). A diagnostic ST↓ threshold of 0.5 mm provided greater discriminatory capacity than a 1.0 mm cutoff (P = .03).

CONCLUSIONS

Among patients selected to undergo coronary angiography, regadenoson-induced ST↓ ≥0.5 mm was associated with higher rates of severe CAD and MACE, irrespective of MPI finding.

Normal Myocardial Perfusion Gated SPECT and Positive Stress Test: Different Prognoses in Women and Men

BACKGROUND

The aim of this study was to analyze different prognoses in women and men with normal myocardial perfusion gated SPECT, according to stress test results.

METHODS

Differences between women and men in terms of hard events (HE) (non-fatal acute myocardial infarction or cardiac death) and HE plus coronary revascularization (HE + CR) were analyzed in 2,414 consecutive patients (mean age 62.8 ± 13.5 years, 1,438 women) with a normal stress-rest gated SPECT, taking into account their stress test results.

RESULTS

Four hundred and seven patients (16.9%) (15.9% women and 17.5% men) had a positive stress test (ST-segment depression ≥1 mm and/or angina). During a follow-up of 5.1 ± 3.4 years, there were more significant HE (6.5% vs 2.3%; P = .005) and HE + CR (11.6% vs 4.8%, P = .001) in men with a positive stress test than in men with a negative stress test. These differences were not observed in women. In multivariate regression models, HE and HE + CR were also more frequent in men with a positive stress test (HR:3.3 [95% CI 1.1% to 9.5%]; HR:4.2 [95% CI 1.8% to 9.9%]; respectively) vs women with a positive stress test.

CONCLUSIONS

Although patients with normal gated SPECT studies have a favorable outcome, men with an abnormal stress test have a more adverse prognosis than women.

The Significance of ST Depression in a Postmenopausal Woman on Estrogen Therapy during Regadenoson Myocardial SPECT Imaging

The incidence of false-positive stress tests has been noted in women, especially on hormone replacement therapy. Current literature describes this phenomenon in treadmill and adenosine stress tests. The introduction of regadenoson as a vasodilator agent has been widely adopted owing to its potency and specificity. To our knowledge, false-positive stress test with regadenoson in a postmenopausal woman on estrogen has never been described. Given the higher chronotropic response with regadenoson, we believe that normal perfusion images with a higher heart rate response indicate a good prognosis in such patients.

Exercise stress tests for detecting myocardial ischemia in asymptomatic patients with diabetes mellitus

The predominant cause of death in diabetes mellitus (DM) is coronary artery disease (CAD). Little is known about prevalence of silent ischemia in developing nations. We compared prevalence of silent ischemia in DM to a control group by exercise myocardial perfusion imaging (MPI) and electrocardiogram (ECG) in developing nations. The prospective multinational Ischemia Assessment with Exercise imaging in Asymptomatic Diabetes study recruited participants at 12 sites in Asia, Africa, and Latin America. DM participants were age- and gender-matched 2:1 to non-DM individuals with ≥1 CAD risk factor. Subjects underwent exercise tests that were interpreted in core labs in blinded fashion. The study included 392 DM and 205 control participants. Among participants with diagnostic ECGs, a similar proportion of DM and controls had ischemic ECG (15% vs 12%, p = 0.5). A significantly higher proportion of DM group had MPI abnormalities compared with controls (26% vs 14%, p <0.001). In participants with ischemia on MPI, only 17% had ischemic ECG, whereas in those without ischemia on MPI, 10% had ischemic ECG. In a multivariable model, DM was independently associated with abnormal MPI (odds ratio 2.1, 95% confidence interval 1.3-3.5, p = 0.004). Women were less likely to have ischemia by MPI than men (10% vs 30%, p <0.001) and concordance between ECG and MPI was much worse in women. In conclusion, in this large prospective study, asymptomatic DM participants had (1) more ischemia by exercise MPI than ECG, (2) more ischemia by MPI but not ECG than control group, and (3) ischemia by MPI was less in women than men.

Electrocardiographic changes during vasodilator SPECT myocardial perfusion imaging: does it affect diagnosis or prognosis?

BACKGROUND

Significance of electrocardiographic (ECG) changes during vasodilator stress myocardial perfusion imaging (MPI) is controversial. We examined the diagnostic and prognostic significance of ECG changes during vasodilator single photon emission computerized tomography (SPECT) MPI.

METHODS

We studied consecutive patients who underwent vasodilator SPECT MPI from 1995 to 2009. Patients with baseline ECG abnormalities, previous history of coronary artery bypass graft surgery or myocardial infarction (MI) were excluded. Significant coronary artery disease (CAD) was defined as >70% stenosis of any vessel or ≥50% stenosis of left main. Mean follow-up was 2.4 ± 1.5 years for cardiac events (cardiac death and non-fatal MI).

RESULTS

Of patients in the diagnostic cohort, ST depression was associated with increased incidence of CAD with abnormal (P = .020 and P <.001) but not in those with normal perfusion (P = .342). Of 3,566 patients with follow-up in the prognostic cohort, including 130 (5.0%) with ST depression and normal perfusion, the presence of ST depression ≥1 mm did not affect the outcomes in any summed stress score category.

CONCLUSIONS

ST depression ≥1 mm during vasodilator SPECT MPI is associated with CAD in patients with abnormal perfusion, but provides no additional risk stratification beyond concomitant perfusion imaging, including those with normal studies.

A blunted heart rate response to regadenoson is an independent prognostic indicator in patients undergoing myocardial perfusion imaging

BACKGROUND

Regadenoson myocardial perfusion imaging (MPI) is a useful method for risk assessment. We hypothesized that the heart rate response (HRR) to regadenoson carries incremental prognostic information to that derived from perfusion pattern and left ventricular (LV) ejection fraction (EF).

METHODS AND RESULTS

The study population included 1,156 (60 ± 13 years, 46% women, 40% diabetes mellitus, 53% chronic kidney disease) patients. During a follow-up period of 22 ± 5 months, 103 patients died (9%). Independent determinants of the HRR included age, gender, race, diabetes mellitus, coronary revascularization, LVEF, use of insulin and aldosterone antagonists. Decreasing HRR was associated with stepwise increase in mortality (log-rank P < .0001). In a Cox proportional model for mortality that adjusted for age, gender, diabetes mellitus, renal disease, and MPI findings, HRR in the lowest quartile was independently associated with fivefold increase in mortality compared to the highest quartile [HR 5.2, 95% CI 2.3-12.0, P < .0001]. Patients with a normal HRR had a relatively low annualized total mortality despite the presence of risk factors. The addition of HRR to traditional MPI findings had a net reclassification improvement of 15%, P = .02.

CONCLUSION

A blunted HRR to regadenoson is an independent predictor of poor outcome, adds incremental value to MPI, and helps in better risk stratification.

The prognostic value of the heart rate response to adenosine in relation to diabetes mellitus and chronic kidney disease

BACKGROUND

Myocardial perfusion imaging (MPI) is a useful method for risk assessment in patients with diabetes mellitus (DM) and chronic kidney disease (CKD), but these patients have a residual risk that is not accounted for by MPI. The objective of this study is to determine whether the heart rate response (HRR) to adenosine has an incremental prognostic value to MPI in high-risk patients.

METHODS

The study group included 879 (age 61 ± 13 years, 48% women, 58% white, 40% DM, 49% CKD) consecutive patients who underwent adenosine MPI. Chronic kidney disease was defined as an estimated glomerular filtration rate <60 mL/min per 1.73 m(2) or dialysis replacement therapy. An HRR <10% (change from baseline) was considered blunted. The outcome of interest was overall mortality.

RESULTS

During a follow-up period of 40 ± 14 months, 212 patients (24%) died. Patients with DM (23.4% ± 16.3% vs 29.4% ± 21.4%, P < .0001) and CKD (22.7% ± 17.6% vs 30.5% ± 20.4%, P < .0001) had lower HRR as compared with patients without DM and CKD, respectively. A blunted HRR was associated with increased mortality in the overall population and in those with DM and CKD and helped in risk stratification when added to traditional MPI findings. In a Cox regression model, a blunted HRR was the strongest predictor of mortality (hazard ratio 2.8, P < .0001) and provided additional prognostic data to MPI (hazard ratio 1.9, P < .0001) after controlling for age, gender, race, history of myocardial infarction, DM, CKD, β-blocker use, and presence of chest pain.

CONCLUSIONS

A blunted HRR to adenosine is an independent predictor of poor outcome, adds incremental value to MPI, and helps in better risk stratification in high-risk patient groups.

Impact of left ventricular dyssynchrony by phase analysis on cardiovascular outcomes in patients with end-stage renal disease

BACKGROUND

Cardiovascular disease is the leading cause of mortality in patients with end-stage renal disease (ESRD). While left ventricular (LV) perfusion pattern and ejection fraction (EF) are important determinant of outcome, the prognostic importance of LV dyssynchrony, which can also be assessed by gated SPECT myocardial perfusion imaging (MPI), has not been well studied in this population.

METHODS AND RESULTS

The indices of LV mechanical dyssynchrony were measured by automated analysis of gated SPECT MPI in patients with ESRD who were evaluated for transplantation at our institution (2001-2004) and who had coronary angiography within 6 months of the evaluation. All-cause mortality data were prospectively collected and verified against the social security death index database. The study population consisted of 144 ESRD patients aged 53 ± 9 years. 35% were women and 63% had diabetes mellitus. The LVEF was 48 ± 12%. They were followed-up for 41 ± 28 months during which time 55 (38%) died prior to renal transplantation. An abnormal QRS duration was not predictive of worse outcomes (log-rank P = .9). The median phase bandwidth (BW) was 62° (inter-quartile range 47-98°) and standard deviation (SD) was 23° (inter-quartile range 15-35°). Patients with a BW above the median had worse survival (log-rank P = .017) and there was a trend toward worse survival in those with a SD above the median (log-rank P = .096). A 2-year mortality was higher in those with BW ≥ 62° in the entire cohort, and in the subsets of patients with normal LVEF (log-rank P = .001), coronary artery disease by angiography, increased LV mass index, QRS <110 ms, and perfusion defect size <20% of the LV.

CONCLUSIONS

LV mechanical dyssynchrony by phase analysis is a predictor of mortality in patients with ESRD. It may have a role in risk-stratifying patients and should be incorporated in future studies using gated MPI.

Positive vasodilator stress ECG with normal myocardial perfusion imaging and its correlation with coronary angiographic findings in African Americans and Hispanics

BACKGROUND

Ischemic electrocardiographic (ECG) changes during vasodilator stress testing (VST) in the presence of abnormal myocardial perfusion imaging (MPI) are uncommon and are associated with presence of multivessel coronary artery disease (CAD). However, there is a paucity of data regarding the significance of ischemic ECG changes during VST with normal MPI in general, and especially among African Americans and Hispanics.

HYPOTHESIS

Ischemic changes during VST with normal MPI are associated with significant CAD.

METHODS

A retrospective review was done of 2945 patients undergoing VST.

RESULTS

Only 20 patients (0.7%) had positive ECG changes with normal MPI. Their demographics were: 60% Hispanic, 40% African American; 85% female; mean age 63 ± 11 years; history of hypertension 80%, diabetes 50%, and dyslipidemia 75%; smokers 30%; atypical chest pain 60%, and typical chest pain 40%. Of these 20 patients, 12 patients underwent coronary angiography. All 12 had significant CAD; nine (75%) had multivessel disease and 3 (25%) had single-vessel disease. Prevalence of clinical variables and risk factors for CAD were similar among both the groups who did and did not undergo coronary angiography.

CONCLUSIONS

Among African Americans and Hispanics, ischemic ECG changes during VST with normal MPI are likely to be associated with significant CAD and may warrant coronary angiography to assess presence and extent of CAD.

Patients with adenosine-induced ST-segment depressions and normal myocardial perfusion imaging: cardiac outcomes at 24 months

BACKGROUND

The significance of ischemic ECG changes during adenosine infusion in patients with normal myocardial perfusion imaging (MPI) is controversial. We evaluated the prevalence of, and defined the predictors for, severe coronary artery disease (CAD) in patients with such discordant findings.

METHODS

The findings of 3700 adenosine MPI studies performed at our institution between June 2005 and March 2009 were reviewed.

RESULTS

Data for 76 patients who had not previously undergone coronary revascularization and who had sufficient follow-up were analyzed; 22 (29%) were referred for coronary angiography and 10 (13%) underwent revascularization. None had left main disease and only three (14%) had multivessel disease. Diabetes mellitus was more prevalent (70% vs. 23%; P = .010) and ischemic ST-segment depressions more often lasted >5 minutes (50% vs. 15%; P = 0.021) in patients undergoing revascularization. During a 24 ± 13 month follow-up period, there were no deaths or myocardial infarctions, while an eleventh patient underwent revascularization 19 months after MPI.

CONCLUSIONS

In the presence of normal MPI, the specificity of ischemic ECG changes during adenosine infusion for the detection of severe obstructive CAD is poor, although patients with multiple coronary risk factors, particularly diabetes mellitus, should undergo further investigation.

Relation between heart rate response to adenosine and mortality in patients with end-stage renal disease

This study examined the relation between heart rate (HR) response to adenosine and outcome in patients with end-stage renal disease (ESRD). The usual HR increase during adenosine infusion was caused by direct sympathetic stimulation. It was hypothesized that a blunted HR response, which was probably caused by sympathetic denervation, would be associated with a worse outcome in patients with ESRD. One hundred thirty-nine patients with ESRD being evaluated for renal transplantation who underwent coronary angiography and adenosine gated single-photon emission computed tomographic myocardial perfusion imaging were followed up for all-cause mortality. Percentage of change in HR (%DeltaHR) was calculated as [(peak HR during adenosine infusion - HR at rest)/HR at rest] * 100. A control group of 54 patients (normal renal function and no diabetes) was included for comparison of HR responses. Mean age of patients was 54 +/- 9 years, 30% were women, and 68% had type-2 diabetes mellitus. %DeltaHR was 19.2 +/- 18% in patients with ESRD versus 33 +/- 25% in the control group (p <0.0001). At a mean follow-up of 3.4 +/- 1.5 years, 50 patients (36%) with ESRD died. %DeltaHR was lower in nonsurvivors than survivors (12.6 +/- 14% vs 23 +/- 19%; p = 0.0017). Patients with %DeltaHR less than the median value were more likely to have lower left ventricular ejection fraction and larger end-diastolic volume (p <0.05 for each). In a multivariate logistic regression model, %DeltaHR alone was an independent predictor of all-cause mortality (adjusted odds ratio 5.5, 95% confidence interval 2.3 to 12.9, p = 0.0001). In conclusion, patients with ESRD had a blunted HR response to adenosine, and degree of blunting was strongly associated with all-cause mortality.

Role of myocardial perfusion imaging in patients with end-stage renal disease undergoing coronary angiography

Patients with end-stage renal disease (ESRD) are at high risk of cardiovascular events. This study examined the prognostic power of stress myocardial perfusion imaging (MPI) in 150 patients with ESRD (mean age 53 +/- 9 years; 30% women; 66% with diabetes mellitus) being evaluated for renal transplantation with known coronary anatomy using angiography. Baseline data in addition to perfusion and angiographic parameters were compared between survivors and nonsurvivors. All-cause mortality was defined as the outcome measure. An abnormal MPI result was present in 85% of patients, 30% had left ventricular (LV) ejection fraction (EF) < or =40%, and 40% had multivessel coronary artery disease using angiography. At a mean follow-up of 3.4 +/- 1.5 years, 53 patients died (35%). LVEF < or =40%, LV dilatation (LV end-diastolic volume >90 ml), and diabetes mellitus were associated with higher mortality (all p <0.05). Both total perfusion defect size and mean number of narrowed coronary arteries using angiography were significantly higher in those who died (p <0.05). In a multivariate model, abnormal MPI results (low LVEF or abnormal perfusion) and diabetes alone were independent predictors of death, whereas number of narrowed arteries using coronary angiography was not. Thus, MPI was a strong predictor of all-cause mortality in patients with ESRD. In conclusion, abnormal MPI results independently predicted worse survival and provided more powerful prognostic data than coronary angiography.

Heart rate response to adenosine in patients with diabetes mellitus and normal myocardial perfusion imaging

Adenosine infusion, as is used in stress single photon-emission computed tomographic (SPECT) imaging, produces an increase in heart rate (HR) and a decrease in blood pressure (BP). The increase in HR is most likely due to direct sympathetic stimulation rather than a reflex to the decrease in BP. In this study, it was hypothesized that the HR response to adenosine is different in patients with versus without diabetes mellitus (DM) in the setting of normal SPECT imaging results. We studied 60 patients with DM (53% women, mean age 62 +/- 10 years) and 60 controls (50% women, mean age 61 +/- 12 years) (p = NS). All patients underwent adenosine SPECT imaging (140 mug/kg/min for 5 minutes) for clinical indications and had normal perfusion and systolic left ventricular function. HR and BP were measured at baseline and during adenosine infusion. HR ratio was defined as peak HR divided by baseline HR and the change as peak HR minus baseline HR. The change in HR (17 +/- 12 vs 22 +/- 14 beats/min, p = 0.034) and the ratio (1.24 +/- 0.20 vs 1.33 +/- 0.25, p = 0.048) were significantly lower in patients with DM compared with those without DM. The baseline and change in mean BP were not significantly different between the 2 groups. In a stepwise regression analysis model, DM was identified as a predictor of the change in HR (p = 0.022). In conclusion, HR response to adenosine infusion is diminished in patients with DM with normal SPECT imaging results. This is likely due to cardiovascular autonomic neuropathy and may carry important prognostic information.

Serial evaluations of myocardial infarct size after alcohol septal ablation in hypertrophic cardiomyopathy and effects of the changes on clinical status and left ventricular outflow pressure gradients

Alcohol septal ablation (ASA) as a treatment for obstructive hypertrophic cardiomyopathy produces septal infarction. There is a concern that such infarcts could be detrimental. Changes in the size of these infarcts by serial perfusion testing have not been studied. We performed resting serial-gated single-photon emission computed tomographic myocardial perfusion imaging in 30 patients (age 51+/-17 years, 57% were women) who had ASA between September 2003 and March 2007 before, 2+/-0.8 days (early), and 8.4+/-6.9 months (late) after ASA. Patients were also followed clinically and with serial 2-dimensional echocardiography. New York Heart Association class decreased from 3.50+/-0.51 before to 1.14+/-0.36 (p<0.0001) 3 months after ASA. The left ventricular (LV) outflow gradient (by Doppler echocardiography) decreased from 63+/-32 mm Hg before to 28+/-23 mm Hg after ASA (p<0.005). None of the patients had perfusion defects at rest before ASA. After ASA, perfusion defect size, involving the basal septum, decreased from 9.4+/-5.8% early to 5.2+/-4.2% of LV myocardium late after ASA (p<0.001). There were no changes in LV size and ejection fraction after ASA. In conclusion, ASA produces small basal ventricular septal infarcts (resting perfusion abnormality) involving<10% of the LV myocardium (including ventricular septum). There is a significant reduction in the perfusion abnormality late after ASA without an increase in LV outflow obstruction or recurrence of symptoms.

Predictors of survival in patients with end-stage renal disease evaluated for kidney transplantation

Cardiovascular disease is the major cause of mortality in patients with end-stage renal disease (ESRD). This study examined the all-cause mortality in 3,698 patients with ESRD evaluated for kidney transplantation at our institution from 2001 to 2004. Mean age for the cohort was 48+/-12 years, and 42% were women. Stress myocardial perfusion imaging was done in 2,207 patients (60%) and coronary angiography in 260 patients (7%). There were 622 deaths (17%) during a mean follow-up period of 30+/-15 months. The presence and severity of coronary disease on angiography was not predictive of survival. Coronary revascularization did not impact survival (p=0.6) except in patients with 3-vessel disease (p=0.05). The best predictor of death was left ventricular ejection fraction, measured by gated myocardial perfusion imaging, with 2.7% mortality increase for each 1% ejection fraction decrease. In conclusion, left ventricular ejection fraction is a strong predictor of survival in patients with ESRD awaiting renal transplantation. Strategies to improve cardiac function or earlier renal transplantation deserve further studies.