Aminophylline and caffeine for reversal of adverse symptoms associated with regadenoson SPECT MPI.

BACKGROUND: Aminophylline shortages led us to compare intravenous (IV) aminophylline with IV and oral (PO) caffeine during routine pharmacologic stress testing with SPECT MPI. METHODS: We measured presence, duration, and reversal of adverse symptoms and cardiac events following regadenoson administration in consecutive patients randomized to IV aminophylline (100 mg administered over 30-60 seconds), IV caffeine citrate (60 mg infused over 3-5 minutes), or PO caffeine as coffee or diet cola. RESULTS: Of 241 patients, 152 (63%) received regadenoson reversal intervention. Complete (CR), predominant (PRE), or partial (PR) reversal was observed in 99%. CR by IV aminophylline (87%), IV caffeine (87%), and PO caffeine (78%) were similar (P = NS). Time to CR (162 ± 12.6 seconds, mean ± SD) was similar in treatment arms. PO caffeine was inferior to IV aminophylline for CR + PRE. CONCLUSIONS: IV aminophylline and IV caffeine provide rapid, safe reversal of regadenoson-induced adverse effects during SPECT MPI. Oral caffeine appeared similarly effective for CR but not for the combined CR + PRE. Our results suggest PO caffeine may be an effective initial strategy for reversal of regadenoson, but IV aminophylline or IV caffeine should be available to optimize symptom reversal as needed.

Quantitative high-efficiency cadmium-zinc-telluride SPECT with dedicated parallel-hole collimation system in obese patients: results of a multi-center study.

BACKGROUND: Obesity is a common source of artifact on conventional SPECT myocardial perfusion imaging (MPI). We evaluated image quality and diagnostic performance of high-efficiency (HE) cadmium-zinc-telluride parallel-hole SPECT MPI for coronary artery disease (CAD) in obese patients. METHODS AND RESULTS: 118 consecutive obese patients at three centers (BMI 43.6 ± 8.9 kg·m(-2), range 35-79.7 kg·m(-2)) had upright/supine HE-SPECT and invasive coronary angiography > 6 months (n = 67) or low likelihood of CAD (n = 51). Stress quantitative total perfusion deficit (TPD) for upright (U-TPD), supine (S-TPD), and combined acquisitions (C-TPD) was assessed. Image quality (IQ; 5 = excellent; < 3 nondiagnostic) was compared among BMI 35-39.9 (n = 58), 40-44.9 (n = 24) and ≥45 (n = 36) groups. ROC curve area for CAD detection (≥50% stenosis) for U-TPD, S-TPD, and C-TPD were 0.80, 0.80, and 0.87, respectively. Sensitivity/specificity was 82%/57% for U-TPD, 74%/71% for S-TPD, and 80%/82% for C-TPD. C-TPD had highest specificity (P = .02). C-TPD normalcy rate was higher than U-TPD (88% vs 75%, P = .02). Mean IQ was similar among BMI 35-39.9, 40-44.9 and ≥45 groups [4.6 vs 4.4 vs 4.5, respectively (P = .6)]. No patient had a nondiagnostic stress scan. CONCLUSIONS: In obese patients, HE-SPECT MPI with dedicated parallel-hole collimation demonstrated high image quality, normalcy rate, and diagnostic accuracy for CAD by quantitative analysis of combined upright/supine acquisitions.

Effect of gender on cardiovascular risk stratification with ECG gated SPECT left ventricular volume indices and ejection fraction.

BACKGROUND: Optimal gender-specific risk prediction using ECG-gated SPECT left ventricular (LV) volumes and ejection fraction (EF) remains undefined despite reported gender differences in baseline LV function. METHODS: ECG-gated SPECT studies of 891 consecutively referred patients (43% women) were evaluated for LV end-systolic and diastolic volume indices (ESVI, EDVI) and EF. Effects of gender on prediction of hard cardiac events (HCE) and the combined endpoint of all-cause mortality or non-fatal infarction (ACMMI) were evaluated. RESULTS: Women had smaller ESVI (37 vs 55 mL/m(2)), EDVI (78 vs 99 mL/m(2)), and higher LVEF (56 vs 47%, P < 0.0001 for each) with equivalent rates of HCE (6.1%) and ACMMI (11.8%). HCE risk started at smaller ESVI and EDVI in women compared to men (P < or = 0.05 for each). In women, ESVI 37 mL/m(2) provided maximum HCE prediction compared to 53 mL/m(2) in men. A 1 mL/m(2) increase in ESVI was associated with a 2.9% increased HCE risk in women (P < 0.0001) and a 0.9% increased ACMMI risk in men (P = 0.03). Women with ESVI > 35 mL/m(2) had HCE HR 12.0 compared to women with ESVI < 23 mL/m(2). CONCLUSION: LV volume indices and LVEF predict subsequent morbid clinical events in men and women. In women, risk of subsequent events started at smaller LV volume indices compared to men despite similar risk profiles.

Prospective serial evaluation of myocardial perfusion and lipids during the first six months of pravastatin therapy: coronary artery disease regression single photon emission computed tomography monitoring trial.

OBJECTIVES: This study was designed to assess prospectively changes in serum lipid profile and myocardial perfusion with serial radionuclide single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) during the first six months of pravastatin therapy. BACKGROUND: Morbid coronary events occur despite statin therapy and lipid-lowering in patients with coronary artery disease (CAD). A reliable strategy to identify responders with effective treatment from nonresponders on statin therapy before clinical events is needed. METHODS: Rest and stress SPECT MPI and lipids were assessed serially in 25 patients (36% women) with CAD and dyslipidemia during the first six months of pravastatin therapy. RESULTS: Total cholesterol, low-density lipoprotein cholesterol, and triglycerides declined (26%, 32%, and 30%, respectively) by six weeks and remained reduced at six months. Mean stress perfusion defect (summed stress score [SSS]) was severe (13.3 +/- 6.0) at baseline, showed no change at six weeks, and improved significantly at six months (10.3 +/- 7.3, p < 0.01). The six-month study SSS improved in 11 (48%) patients, was unchanged in 10 (43%) patients, and worsened in 2 (9%) patients. Changes in lipid levels did not reliably predict changes in myocardial perfusion at six weeks or six months in this small pilot study. CONCLUSIONS: Serial SPECT MPI demonstrated improved stress myocardial perfusion in 48% of patients treated for six months with pravastatin. Time course of improved myocardial perfusion during pravastatin therapy is delayed compared to lipids. Direction and magnitude of changes in the myocardial perfusion vary and do not correlate closely with improvements in lipids.