Successful CTO PCI is associated with reduced long-term cardiac mortality and need for coronary artery bypass graft surgery. Treatment of CTO with DES rather than BMS is associated with a significant reduction in target vessel revascularization with similar rates of stent thrombosis. Paclitaxel-eluting stents and sirolimus-eluting stents had similar long-term safety and efficacy outcomes.
OBJECTIVES
To evaluate the relationship between platelet reactivity and atherosclerotic burden in patients undergoing percutaneous coronary intervention (PCI) with pre-intervention volumetric intravascular ultrasound (IVUS) imaging.
BACKGROUND
Atherosclerosis progresses by the pathologic sequence of sub-clinical plaque rupture, thrombosis and healing. In this setting, increased platelet reactivity may lead to more extensive arterial thrombosis at the time of plaque rupture, leading to a more rapid progression of the disease. Alternatively, abnormal vessel wall biology with advanced atherosclerosis is known to enhance platelet reactivity. Therefore, it is possible that by either mechanism, increased platelet reactivity may be associated with greater atherosclerotic burden.
METHODS
We analyzed patients who underwent PCI with pre-intervention IVUS imaging and platelet reactivity functional assay (P2Y12 reaction-units [PRU]) performed >16 hours post-PCI after stabilization of clopidogrel therapy (administered pre-PCI). A PRU value of >230 defined high on-treatment platelet reactivity (HPR).
RESULTS
Among 335 patients (mean age 65.0; 71% male), there were 109 patients with HPR (32.5%) and 226 without HPR (67.5%), with HPR being associated with diabetes and chronic renal insufficiency. By IVUS analysis, HPR patients had significantly greater target lesion calcium length, calcium arc, and calcium index. Furthermore, HPR patients tended to have longer lesions and greater volumetric dimensions, indicating higher plaque volume, larger total vessel volume and also greater lumen volume, despite similar plaque burden. By multivariable analysis controlling for baseline clinical variables, HPR was the single consistent predictor of all IVUS parameters examined, including plaque volume, calcium length and calcium arc.
CONCLUSIONS
Increased platelet reactivity on clopidogrel treatment, as defined by a PRU value of >230, is associated with greater coronary artery atherosclerotic disease burden and plaque calcification.
Skeletal myoblast (SM) implantation promotes recovery of myocardial function after ischemic injury. Clinical observations suggest an association of SM implantation and ventricular arrhythmias. Support for this link has been sought in animal studies, but none employing models of congestive heart failure. In a canine model of postinfarction congestive heart failure (CHF) we compared the frequency of rhythm disturbances using ambulatory electrocardiography monitoring following skeletal myoblast or saline (SAL) implantation. In 19 mongrel dogs ischemic injury and CHF were induced by intracoronary microsphere infusions. Direct intramyocardial injection of autologous skeletal myoblasts (ASM) (2.7-8.3 x 10(8) cells) or SAL controls was administered to 11 and 8 dogs, respectively. Serial echocardiography and 24-h ambulatory electrocardiography were recorded at baseline (after CHF induction) and at 4 weeks and at 8-10 weeks after injection. Comparisons between groups of left ventricular ejection fraction (LVEF) and the frequency of ventricular arrhythmias, supraventricular arrhythmias, and measures of heart rate variability (HRV) were made at each of the three time points. LVEF increased from 41 +/- 6% to 47 +/- 2% (p < 0.03) in the ASM group, and did not change (42 +/- 6% to 40 +/- 2%, p = ns) in SAL. After injection, no differences were seen in the number of dogs demonstrating ventricular tachycardia (n = 3 vs. n = 2, p = ns) or frequent PVCs (n = 3 vs. n = 3, p = ns) in the ASM versus SAL groups, respectively. Significant changes were observed in a time-domain measure of HRV, standard deviation of normal-to-normal RR interval (in ms: 4 weeks 174 +/- 95 vs. 242 +/- 19; 8 weeks 174 +/- 78 vs. 276 +/- 78, ASM vs. SAL), but not in other time domain parameters. In this canine model of ischemic CHF, ASM implantation did not result in a significant increase in ventricular arrhythmias compared to controls animals. The potential for ASM implantation to affect time-domain parameters of HRV merits further study.
SummaryA 78-year-old, retired Caucasian male presented in emergency room with 3 days history of progressive watery diarrhoea. Two weeks earlier, he received intravenous levofl oxacin for community acquired pneumonia. The patient was diagnosed as severe Clostridium diffi cile infection based on clinical presentation, labs and imaging studies. The patient was initially treated with intravenous metronidazole and oral vancomycin. While awaiting subacute rehabilitation placement, the patient relapsed twice. After fi rst recurrence the patient was treated with 2 weeks of oral nitazoxanide. After second recurrence, the patient was treated 2 weeks of nitazoxanide followed by tapering dose of vancomycin. The patient was followed and no relapse was reported at 1 year follow-up visit.
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