Longitudinal myocardial function is more compromised in cardiac syndrome X compared to insignificant CAD: Role of stress echocardiography and calcium scoring.

BACKGROUND AND AIM: The aim of this study was to assess the nature of myocardial dysfunction in the cardiac syndrome X (CSX) and insignificant coronary artery disease (ICAD) using dobutamine stress echocardiography (DSE) and coronary calcium scoring (CAC). METHODS: We prospectively studied 35 consecutive patients who complained of exertional angina, had ≥1 mm ST shift on exercise stress test but normal or no obstructive CAD (<50%) on angiography. Patients were divided into CSX (n = 27) with normal arteries and ICAD (n = 8) with insignificant stenosis. RESULTS: CSX patients had more females, lower calcium score and less prevalent cardiac risk factors compared to ICAD (p < 0.05 for all). At peak stress, MAPSE and TAPSE failed to increase in both groups. LV septal and lateral s' increased in the two groups but the increment increase was less in CSX than ICAD (p < 0.05) while other diastolic indices did not differ between groups (p > 0.05 for all). CAC correlated modestly with LV and RV systolic velocities: septal s' (r = -0.65, p < 0.001) lateral s' (r = -0.35, p = 0.04) and right s' (r = -0.53, p = 0.005) in CSX, while in ICAD patients only with RV s' (r = -0.58, p = 0.02). On multivariate model, only septal s' OR 1.816 (1.1090-3.820, p = 0.04) proved the most powerful independent predictor of CAC. CONCLUSIONS: Compromised LV longitudinal systolic velocities were more pronounced and calcium score as a surrogate for atherosclerosis was lower in CSX than ICAD. These findings strengthen the evidence for different pathogenesis of CSX compared to ICAD, with microvascular disease in the former and calcification in the latter.

Coronary calcification compromises myocardial perfusion irrespective of luminal stenosis.

AIM: The aim of this study was to evaluate the relationship between coronary artery calcification (CAC) assessed by multi-detector computed tomography (MDCT) and myocardial perfusion assessed by cardiac magnetic resonance imaging (CMR) in a group of symptomatic patients. METHOD: Retrospective analysis of 120 patients (age 65.1 ± 8.9 years, 88 males) who presented with atypical chest pain to Bethanien Hospital, Frankfurt, Germany, between 2007 and 2010 and who underwent CAC scoring using MDCT, CMR, and conventional coronary angiography. Patients were divided into those with high-grade (HG) stenosis (n = 67, age 65.1 ± 9.4 years) and those with no-HG stenosis (n = 53, age 65.1 ± 8.6 years). RESULTS: There were more males with HG stenosis (82.1% vs. 62.3%, p = 0.015), in whom the percentage and number of abnormal perfusion segments were higher at rest (37.3% vs. 17%, p = 0.014) but not different with stress (p = 0.83) from those with no-HG stenosis. Thirty-four patients had myocardial perfusion abnormalities at rest and 26 patients developed perfusion defects with stress. Stress-induced myocardial perfusion defects were 22.4% sensitive and 79.2% specific for detecting HG stenosis. The CAC score was lower in patients with no-HG stenosis compared to those with HG stenosis (p < 0.0001). On the ROC curve, a CAC score of 293 had a sensitivity of 71.6% and specificity of 83% in predicting HG stenosis [(AUC 0.80 (p < 0.0001)]. A CAC score of 293 or the presence of at least 1 segment myocardial perfusion abnormality was 74.6% sensitive and 71.7% specific in detecting HG stenosis, the respective values for the 2 abnormalities combined being 19.4% and 90.6%. The severity of CAC correlated with the extent of myocardial perfusion in the patient group as a whole with stress (r = 0.22, p = 0.015), particularly in those with no-HG stenosis (r = 0.31, p = 0.022). A CAC score of 293 was 31.6% sensitive and 87.3% specific in detecting myocardial perfusion abnormalities. CONCLUSION: In a group of patients with exertional angina, coronary calcification is more accurate in detecting high-grade luminal stenosis than myocardial perfusion defects. In addition, in patients with no stenosis, the incremental relationship between coronary calcium score and the extent of myocardial perfusion suggests coronary wall hardening as an additional mechanism for stress-induced angina other than luminal narrowing. These preliminary findings might have a clinical impact on management strategies of these patients other than conventional therapy.