Impact of elective PCI on left intraventricular mechanical dyssynchrony in patients with chronic stable angina (tissue Doppler study)

Myocardial ischemia and previous infarction contribute to left ventricular dyssynchrony in patients with coronary artery disease

AIMS

The aim of this study was to characterize determinants of left ventricular mechanical dyssynchrony (LVMD) in patients with coronary artery disease (CAD).

METHODS

Medical records and results of myocardial perfusion SPECT/CT studies were evaluated in 326 patients with previously diagnosed CAD. LVMD was assessed with the phase analysis of ECG-gated myocardial SPECT. Dyssynchrony was described with phase histogram bandwidth (PHBW), standard deviation (PHSD) or entropy (PHE) values above limit of the highest normal.

RESULTS

Prevalence of LVMD was 29% in CAD patients. Size of the infarction scar and ischemia extent correlated significantly with PHBW, PHSD and PHE (P < 0.001 for all). Independent predictors of LVMD were myocardial infarction scar (P = 0.004), ischemia extent (P = 0.003), and QRS duration (P = 0.003). Previous percutaneous coronary intervention and coronary artery bypass grafting did not independently predict dyssynchrony.

CONCLUSIONS

Almost one-third of CAD patients had significant LVMD. Dyssynchrony was associated with earlier myocardial infarction and presence of myocardial ischemia. Previous percutaneous coronary intervention and coronary artery bypass grafting did not independently predict dyssynchrony.

The Effect of Clinical Characteristics and Stent Parameters on Left Ventricular Mechanical Dyssynchrony

Aim. To study short term effect of stent size and number on left ventricular mechanical dyssynchrony after elective percutaneous coronary intervention (PCI) to left anterior descending (LAD) artery.

Materials and methods. the study included 150 adult patients with LAD lesion treated with PCI using drug-eluting stent. Patients were evaluated pre PCI then 1 month and 3 months post PCI for evaluation of mechanical dyssynchrony using tissue synchronization image (TSI).

Results. Before revascularization mean left ventricular ejection fraction was 51.2±5.7 %, mean time to peak TSI was 213.6±10.9 ms; 1 month after PCI TSI improved significantly to 163.7±17.6 ms (p<0.001), 3 months after PCI showed more improvement to 120.7±26.9 ms (p<0.001). After 3m; 61 patients (40.7%) showed recovery to normal TSI value. The predictors of non-improvement of time to peak TSI after 3 months were diabetes mellitus (p=0.007), dyslipidemia (p=0.001) and stent length (p=0.001), number of stents (p=0.004). There were strong negative correlation between stent length and improvement of the time to peak TSI at 1 month (r=-0.352, p<0.001) and at 3 months (r=-0.509, p<0.001),and also with number of stent at 1 month (r= -0.173, p=0.034) and at 3 months (r=-0.499, p<0.001), but the correlation between stent diameter and improvement of the TSI wasn’t significant neither at 1 month nor at 3 months (r=0.055, p=0.504 and r= -0.018, p=0.827) respectively.

Conclusion. Increased number and length of the implanted stents were predictors to non-improvement of mechanical dyssynchrony, while stent diameter didn’t affects the recovery.