Impact on adenosine stress cardiac magnetic resonance for recanalisation and follow up of chronic total coronary occlusions

Repeat revascularization: Percutaneous coronary intervention after coronary artery bypass graft surgery

Repeat myocardial revascularization procedures are markedly different from de novo interventions, with increased procedural risk and technical-demanding complexity. However the number of patients previously treated with coronary artery bypass graft (CABG) that need a repeat revascularization due to graft failure is increasing consistently. Late graft failure, usually caused by saphenous vein grafts (SVG) attrition, is certainly not uncommon. However PCI on degenerated SVG presents higher complication rate and worse clinical outcome compared with native arteries interventions. In acute graft failure setting, PCI represents a valuable option to treat postoperative myocardial infarction.

Assessment of Inducible Myocardial Ischemia, Quality of Life, and Functional Status After Successful Percutaneous Revascularization in Patients With Chronic Total Coronary Occlusion

The benefits of chronic total coronary occlusion (CTO) revascularization are not well established. In this prospective cohort study, 47 consecutive patients with successful percutaneous recanalization of CTO underwent adenosine stress cardiac magnetic resonance (CMR), 6-minute walk test (6MWT), and the Short Form-36 Health Survey before and 6 months after the procedure. Successful recanalization of a CTO was followed by significant improvement of (1) global physical and mental health status; (2) the distance walked in the 6MWT; (3) the incidence of chest pain at the end of the 6MWT; and (4) the score of a novel CMR ischemic burden index on the basis of the characteristics of adenosine stress perfusion defects (extension, persistence, transmurality, and induced contractile regional dysfunction). Patients with greater CMR ischemic index before percutaneous revascularization showed better improvement in the 6MWT. In conclusion, successful recanalization of a CTO leads to a concurrent improvement in ischemic burden, exercise tolerance, angina frequency, and quality of life scores. Patients with a high ischemic CMR score before CTO recanalization showed the better improvement in exercise tolerance.

How to Utilize Coronary Computed Tomography Angiography in the Treatment of Coronary Artery Disease

Coronary computed tomography angiography (CCTA) has high negative predictive power for detecting coronary artery disease. However CCTA is limited by moderate positive predictive power in the detection of myocardial ischemia. This is not unexpected because the diameter of a stenosis is a poor indicator of myocardial ischemia and discrepancy between the severity of stenosis and noninvasive tests is not uncommon. The value of stenosis for predicting future development of acute coronary syndrome represented by plaque rupture has been questioned. CCTA identifies the characteristics of high-risk plaque including positive remodeling, low density plaque and spotty or micro-calcification. Also, additional evaluation of myocardial ischemia using computational flow dynamics, and luminal attenuation gradient are expected to increase both diagnostic performance for hemodynamically significant stenosis and the predictive power for future cardiovascular risk. Technical advances in CCTA would enable evaluation of both coronary artery stenosis and myocardial ischemia simultaneously with high predictive performance, and would improve vastly the clinical value of CCTA.

Stress cardiovascular MR in routine clinical practice: referral patterns, accuracy, tolerance, safety and incidental findings

OBJECTIVE

The use of stress cardiovascular MR (CMR) to evaluate myocardial ischaemia has increased significantly over recent years. We aimed to assess the indications, incidental findings, tolerance, safety and accuracy of stress CMR in routine clinical practice.

METHODS

We retrospectively examined all stress CMR studies performed at our tertiary referral centre over a 20-month period. Patients were scanned at 1.5 T, using a standardised protocol with routine imaging for late gadolinium enhancement. Angiograms of patients were assessed by an interventional cardiologist blinded to the CMR data.

RESULTS

654 patients were scanned (mean age 65±29 years; 63 inpatients; 9.6%). 14% of patients had incidental extracardiac findings, the commonest being liver or renal cysts (6%) and pulmonary nodules (4%). 639 patients (97.7%) received intravenous adenosine, 10 received intravenous dobutamine and 5 patients had both. Of the 15 patients who received dobutamine, 12 had no side-effects/complications, 2 experienced nausea and 1 chest tightness. Of the 644 patients who received adenosine, 43% experienced minor symptoms, 1% had transient heart block and 0.2% had severe bronchospasm requiring termination of infusion. There were no cases of hospitalisation or myocardial infarction. 241 patients also had coronary angiography. For detecting at least moderate stenosis of ≥50%, sensitivity was 86%, specificity 98% and accuracy 89%. For detecting severe stenoses of ≥70%, sensitivity was 91%, specificity 86% and overall accuracy 90%. These results compare very favourably with previous smaller research studies and meta-analyses.

CONCLUSION

We conclude that stress CMR, with adenosine as the main stress agent, is well tolerated, safe and accurate in routine clinical practice.