Left main coronary artery disease: A review of the spectrum of noninvasive diagnostic modalities.

Medically managed significant left main (LM) stem disease has been considered a determinant of increased cardiac mortality approaching 50% at 3-year follow-up. Despite the clinical significance of LM disease, studies comparing the various diagnostic modalities, especially noninvasive, are sparse. Clinicians, particularly imagers, should be aware of the strengths and weaknesses of existing modalities to diagnose LM disease as integrating many clues (history, symptoms, electrocardiogram, and stress hemodynamics are essential to suspect this diagnosis and proceed to the next step). Here we review the existing data on the current role of electrocardiography, nuclear myocardial perfusion imaging (single photon emission computed tomography and positron emission tomography), stress echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging in diagnostic evaluation of LM disease. Wherever applicable we have extended our discussion to multivessel coronary artery disease encompassing scenarios where LMS can present as LM equivalent with or without extensive multivessel coronary artery disease.

Comparison of hemodynamic and stress testing variables in patients undergoing regadenoson stress myocardial perfusion imaging to regadenoson with adjunctive low-level exercise myocardial perfusion imaging.

BACKGROUND: Regadenoson (REG), a selective adenosine A2a receptor agonist, is becoming the preferred pharmacologic agent for stress myocardial perfusion imaging (MPI). Hemodynamic and stress variables, immediate safety and use of aminophylline when using REG combined with low-level exercise (REG WALK MPI) compared with REG MPI, have not been well studied and formed the basis of our study. METHODS: Retrospective evaluation of patients who underwent REG MPI (n = 887) was compared to patients undergoing REG WALK MPI (n = 485) from January to November 2009. Patient demographics, hemodynamic parameters, REG MPI data, side effects, immediate major clinical events, and use of aminophylline were evaluated. RESULTS: Patients in REG WALK MPI group tended to be younger, male and obese compared to patients in REG MPI group. REG WALK MPI patients had higher stress heart rate (103 ± 20.5 vs 84 ± 19 bpm, P = .001), higher heart rate reserve (36.3 ± 19 vs 14.7 ± 15.5 bpm, P < .001), and greater systolic blood pressure rise (4.8 ± 21.3 vs -8.9 ± 19.8 mm Hg, P < .001), compared to REG MPI patients. No major adverse events were reported immediately after REG WALK MPI. There were no differences in drug-related side effects in between the two groups; however, the use of aminophylline was lower in REG WALK MPI Group (5.6% vs 11.4%, P = .001). CONCLUSION: REG WALK MPI gives more favorable hemodynamic response with lesser use of aminophylline and no increase in adverse events when compared with REG MPI.

Rationale, design, and goals of the Advanced Cardiovascular Imaging Consortium (ACIC): A Blue Cross Blue Shield of Michigan collaborative quality improvement project.

BACKGROUND: Coronary computed tomography angiography (CCTA) is an emerging noninvasive anatomical method for evaluation of patients with suspected coronary artery disease (CAD). Multicenter clinical registries are key to efforts to establish the role of CCTA in CAD diagnosis and management. The Advanced Cardiovascular Imaging Consortium (ACIC) is a statewide, multicenter collaborative quality initiative with the intent to establish quality and appropriate use of CCTA in Michigan. METHODS: The ACIC is sponsored by the Blue Cross Blue Shield of Michigan/Blue Care Network, and its 47 sites include imaging centers that offer CCTA and meet established structure and process standards for participation. Patients enrolled include those with suspected ischemia with or without known CAD, and individuals across the entire spectrum of CAD risk. Patient demographics, history, CCTA scan-related data and findings, and 90-day follow-up data are entered prospectively into a centralized database with strict validation tools and processes. Collaborative quality initiatives include radiation dose reduction and appropriate CCTA use by education and feedback to participating sites and referring physicians. CONCLUSIONS: Across a wide range of institutions, the ACIC permits evaluation of "real-world" utilization and effectiveness of CCTA and examines an alternative, nontraditional approach to utilization management wherein physicians and payers collaborate to address the growing problem of cardiac imaging overutilization.

Coronary CT angiography after stress testing: an efficient use of resources? Implications of the Advanced Cardiovascular Imaging Consortium (ACIC) results.

Coronary CT angiography (CCTA) has matured to be a fast noninvasive imaging test in the evaluation of coronary artery disease (CAD). It has demonstrated excellent accuracy for defining the presence and the severity of luminal coronary artery stenoses and is probably the best noninvasive test to reliably exclude atherosclerotic coronary disease. Furthermore, accumulating CCTA data indicate that it can identify individuals at risk for all-cause mortality. It is also well known that despite the wealth of data regarding diagnostic and prognostic values of stress testing in CAD, up to 10% of stress imaging studies are considered inconclusive, leading to subsequent invasive coronary angiography for definitive diagnosis often with negative results. Moreover, recent data indicate that up to 30 % of patients undergoing angiography have no significant CAD despite a majority of them having had a prior stress test. Whether CCTA can serve as a cost-effective methodology to invasive angiography has been a source of active research. In this context, we will discuss the implications of the recently published data from the Advanced Cardiovascular Imaging Consortium registry looking at the use of CCTA after stress testing in Michigan.

A randomized, double-blind, placebo-controlled study of the safety and tolerance of regadenoson in subjects with stage 3 or 4 chronic kidney disease.

BACKGROUND: The safety and tolerability of regadenoson, a pharmacologic stress agent that is excreted primarily by the kidneys, were examined in subjects with chronic kidney disease (CKD). METHODS: This multicenter, double-blind, randomized, placebo-controlled study involved men and women, ≥18 years of age, with stage 3 or 4 [estimated glomerular filtration rate (eGFR) 30-59 mL/minute/1.73 m(2) and 15-29 mL/minute/1.73 m(2), respectively] CKD and known or suspected coronary artery disease. Subjects were randomized 2:1 to receive one 10-second intravenous injection of regadenoson 0.4 mg or placebo. The primary outcome measure was the frequency of serious adverse events over 24-h post-dose. RESULTS: The study included 432 subjects with stage 3 (regadenoson n = 287; placebo n = 145) and 72 with stage 4 (regadenoson n = 47; placebo n = 25) CKD. No serious adverse events or deaths were reported over 24-h post-dose. The overall adverse event incidence was higher with regadenoson than placebo (62.6% vs 21.2%; P < .0001). Of the most common adverse events (≥5%) reported by subjects receiving regadenoson, headache (24.9% vs 7.1%), dyspnea (19.2% vs 0.6%), chest discomfort (14.7% vs 0.6%), nausea (14.7% vs 1.2%), flushing (12.0% vs 1.8%), and dizziness (9.6% vs 0.6%) occurred significantly more often (P < .0001) with regadenoson than placebo. There were no trends for clinically meaningful changes in eGFR from baseline to 24-h post-dose in subjects with stage 3 or 4 CKD. CONCLUSIONS: Regadenoson was not associated with any serious or unexpected adverse events in subjects with stage 3 or 4 CKD.

Regadenoson is a safe and well-tolerated pharmacological stress agent for myocardial perfusion imaging in post-heart transplant patients.

BACKGROUND: The safety and tolerability of regadenoson (REG), a newer adenosine A(2a) receptor agonist, has not been tested in orthotopic heart transplant (OHT) patients. METHODS: Retrospective review of a tertiary care center experience of OHT patients who underwent a REG single-photon emission computed tomography (SPECT) study as part of the work-up for cardiac allograft vasculopathy. The control group included those same patients who had prior adenosine-based SPECT. RESULTS: A total of 40 patients met the above criteria. Mean time from OHT to adenosine-SPECT and REG-SPECT was 8.2 ± 4.8 years vs 9.8 ± 4.5 years, respectively (P < .001). Both vasodilators had similar side effect profiles (P = .10), produced significant heart rate acceleration and asymptomatic hypotension (P < .001). There were no episodes of bradycardia and/or AV block with REG. Despite adjustment for medication status, adenosine was still associated with more conduction abnormalities (8 vs 1 event with REG, P = .02) including five episodes of 2nd degree AV block (Mobitz type II) and three episodes of sinus pause. CONCLUSION: This is the first reported use of REG in OHT patients. REG appears to be safe and well tolerated without significant cardiovascular adverse events.

Safety of regadenoson as a pharmacologic stress agent for myocardial perfusion imaging in chronic kidney disease patients not on hemodialysis.

BACKGROUND: Pharmacokinetic studies suggest delayed clearance of Regadenoson (REG), a new selective A2A receptor agonist in chronic kidney disease (CKD). The safety of REG in large series of CKD patients in daily clinical practice remains unstudied. METHODS: Retrospective study of patients with eGFR < 60 mL/min (n = 411, Grp 1, CKD) were compared to patients with eGFR ≥ 60 mL/min (n = 638, Grp 2, Control) undergoing REG-SPECT from Jan to Nov 2009. Patient demographics, REG-SPECT data, side effects, and arrhythmia occurrences were evaluated. RESULTS: No major adverse events were noted immediately after REG-SPECT or at 1 week of follow-up. There were no differences in any arrhythmias in between the two groups (Grp 1, 47.2% vs Grp 2, 42.9%, P = ns). Ninety-nine percent of arrhythmias in CKD patients were PACs or PVCs. Transient junctional rhythm was observed in one CKD patient. There were no occurrences of second degree or higher degree AV block. Grp 1 had a blunted heart rate response (16.6 ± 16.1 vs 24.9 ± 20.3 bpm, P ≤ .001) and greater systolic blood pressure drop response (-7.4 ± 21.1 vs -1.4 ± 20.9 mm Hg, P ≤ .001) compared to Grp 2. Transient headache was more in Grp 2 (15.8% vs 22.6%, P ≤ .007). Aminophylline use to ward-off the side effects was comparable (9.5% vs 9.9%, P = ns). CONCLUSION: REG-SPECT can be safely performed in CKD non-dialysis patients with excellent tolerability, minimal side effects, and favorable hemodynamic responses compared to control group.