Prevalence and risk factors of clopidogrel non-response among Saudi patients undergoing coronary angiography.

OBJECTIVES: To estimate the prevalence of clopidogrel non-response and identify its risk factors among Saudi patients.  METHODS: This cross-sectional study was conducted at Prince Sultan Cardiac Center, Riyadh, Kingdom of Saudi Arabia between January and June 2013, to assess the degree of platelet inhibition using the VerifyNow assay (Accumetrics, San Diego, CA, USA) after receiving clopidogrel standard loading dose. Clopidogrel resistance was defined as ≤15% platelet inhibition or greater than 213 P2Y12 reaction units (PRU).  RESULTS: Three hundred and four patients were included in the study. The mean age was 60.3 ± 11.4 years, and 73% were males. Clopidogrel doses were 300 mg (57%), 600 mg (27%), and 75 mg (16%). All patients used aspirin (81 mg in 94%). Approximately 66% (200/304) showed in vitro clopidogrel non-response, 54% had low platelet inhibitions, and 61% had high post-loading PRU. Using multivariate regression analysis that included all significant characteristics; only diabetes (odds ratio [OR]: 2.36, 95% confidence interval [CI]: 1.30-4.27, p=0.005) and higher preloading PRU (OR: 2.39, 95% CI: 1.40-4.11, p=0.002) remained significantly associated with higher clopidogrel non-response while myocardial infarction (OR: 0.34, 95% CI: 0.15-0.81, p=0.014) remained significantly associated with lower clopidogrel non-response. The associations of morbid obesity and diuretics use with higher clopidogrel non-response were slightly attenuated.   CONCLUSION: Our findings indicate a high rate of clopidogrel in-vitro non-response among Saudi patients undergoing coronary angiography.

Choice of stent and outcomes after treatment of drug-eluting stent restenosis in highly complex lesions.

OBJECTIVES: Our aim was to compare the outcomes of a same versus different drug-eluting stent (DES) implantation strategy for the treatment of DES instent restenosis (ISR). BACKGROUND: The absence of clear data renders the treatment of DES ISR one of the most challenging situations in interventional cardiology. METHODS: We identified all cases of DES ISR treated with a second DES between January 2004 and January 2009. The lesions were divided into those treated with the same DES as the initial one that restenosed and those treated with a different DES. The main end-point was repeat target lesion revascularization (TLR). RESULTS: We included 116 patients with a total of 132 lesions. The patient population was highly complex: 55.5% with diabetes, 56% with type-C lesions, 15.9% with lesions previously stented with BMS and 18.2% with fluoroscopic evidence of stent fracture. A same and different stent strategy was conducted in 41 lesions (31%) and 91 lesions (69%), respectively. Overall TLR was 31.1% and occurred in 46.3% of patients treated with the same stent and 24.4% of those with a different stent (P = 0.012). Multivariable analysis found same stent strategy (OR 2.84, 95%CI 1.23-6.57;P = 0.014) and occurrence of stent fracture (OR 4.03, 95%CI 1.33-12.01;P = 0.012) to be the only independent predictors of TLR after a median follow-up of 20.4 [12.1-30.2] months. CONCLUSIONS: In highly complex lesions, DES implantation for DES ISR is linked to a high need of future revascularization. An association between implanting a DES type other than the original and lower rate of TLR is suggested.

Decreased risk of stent fracture-related restenosis between paclitaxel-eluting stents and sirolimus eluting stents: results of long-term follow-up.

OBJECTIVE: To compare the outcomes between paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) for the treatment of drug-eluting stent (DES) fracture. BACKGROUND: DES fracture is considered as an important predictor of in-stent restenosis (ISR). However, little data are available evaluating the optimal treatment for this complication of coronary stenting. METHODS: From January 1, 2004 to December 31, 2008, patients with DES ISR treated with a second DES were identified and evaluated for stent fracture. Stent fracture was defined by the presence of strut separation in multiple angiographic projections, assessed by two independent reviewers. Target lesion revascularization (TLR) at 6 and 12 months were the primary end points. RESULTS: Of 131 lesions with DES ISR treated with a second DES, we found 24 patients (24 lesions, 18.2%) with angiographically confirmed stent fracture. Of these, 20 patients (20 lesions) treated with either PES (n = 11/55%) or SES (n = 9/45%) were included in the study. TLR at 6 months occurred in 9% of patients treated with PES and 22% of those treated with SES (P = 0.41). After 12 months, TLR was 9% and 55.5%, respectively (P = 0.024). CONCLUSIONS: This study demonstrates a high incidence of stent fracture in patients presenting with DES ISR in need of further treatment with another DES. The suggested association between treatment of stent fracture-associated DES ISR with PES as compared with SES, and better long-term outcomes, is in need of confirmation by larger prospective registries and randomized trials.

Efficacy of a single dose intravenous heparin in reducing sheath-thrombus formation during diagnostic angiography: A randomized controlled trial.

BACKGROUND: Femoral arterial sheath thrombosis and distal embolization are well-recognized complications of cardiac catheterization but the occlusion is extremely rare. Heparinized saline flushes are used during diagnostic coronary angiography to prevent thrombus formation within the sheath lumen. However, the use of prophylactic intravenous heparin following the femoral arterial sheath insertion is controversial. The aim of this study is to evaluate the effectiveness of 2000 units of intravenous heparin bolus in comparison to a saline placebo on the thrombus formation within the arterial sheath during the diagnostic coronary angiography. METHODS: Eligible patients were randomized to receive either a study drug or placebo at the time of femoral sheath insertion. The sheath was aspirated and flushed for any presence of thrombus after each catheter exchange and at the end of the procedure. Five milliliters of blood were extracted and visualized on clean gauze followed by a saline flush. The primary end-point was the effectiveness of the study drug on reducing the incidence of sheath-thrombus formation. RESULTS: Three hundred and twenty patients were randomized into two arms. Three hundred and four patients were analyzed: 147 patients in heparin arm and 157 patients in placebo arm after exclusion of 13 patients in heparin arm and three in placebo arm because of incomplete reports. The baseline characteristics were similar and sheath-thrombi formation was observed in 20% of the total cohort. Of the heparin arm, 12% (19 patients) developed sheath-thrombus formation, whereas 26% (42 patients) in the placebo arm, p-value = 0.002. An adjusted logistic regression model showed that the only predictor for the sheath-thrombus formation was the study drug (i.e. heparin). The odds ratio of developing a thrombus in the control arm was 2.5 (95% CI: 1.4-4.5, p = 0.003). There were no bleeding events observed. CONCLUSION: The risk of thrombus formation is significant and intravenous heparin significantly reduced thrombus formation during diagnostic coronary angiography, with no excess bleeding events.

Stent fracture after everolimus-eluting stent implantation.

Compared with bare-metal stents, drug-eluting stents (DES) have greatly reduced the risk of in-stent restenosis (ISR) by inhibiting neointimal growth. Nevertheless, DES are still prone to device failure, which may lead to cardiac events. Recently, stent fracture (SF) has emerged as a potential mechanism of DES failure that is associated with ISR. Stent fracture is strongly related to stent type, and prior reports suggest that deployment of sirolimus eluting stents (SES) may be associated with a higher risk of SF compared to other DES. Everolimus eluting stents (EESs) represent a new generation of DES with promising results. The occurrence of SF with EES has not been well established. The present paper describes two cases of EES fracture associated with ISR.