Additionally, the largest meta-analysis of randomized trials was conducted in and included ten sub- trials with a total of 33, patients. It compared 3—6 months duration versus 12 months, and it concluded that there is no difference of all-cause of death or MI, or stent thrombosis. Also, comparing 18—48 to 12 months durations showed no difference in the incidence of all cause of death, however a decrease in MI and in stent thrombosis was noted 4.
The basic idea behind the rebound phenomenon is the production of hyper-reactive platelets following the cessation of Clopidogrel. A systematic review by Gaglia and Waksman, found earlier studies to be flawed and more recent detailed analyses elicited doubt on a clinical rebound particular to Clopidogrel. This leads to the belief that the increase in acute coronary and other vascular events after stopping DAPT is due to premature discontinuation or disruption of treatment while the thrombotic risk is still high 6.
The opening of the blockage with the stent causes some breaks in the plaque and injury to the most inner layers of the blood vessel wall. This releases some clotting factors, activates platelets and exposes tissue triggering the formation of platelet-rich blood clots inside the artery.
This can result in acute or subacute stent thrombosis and lead to myocardial infarction and death. Early in the s, full and aggressive systemic anti-coagulation INR of was implemented to reduce stent thrombosis. This approach was marred by complications varying from bleeding to vascular complications and significantly increased the length of hospital stay. In , Dr Antonio Colombo proposed a new ultrasound-guided Intra-Vascular Ultrasound System: IVUS intracoronary stent implantation technique combined with aspirin and ticlopidine anti-platelet agent as a replacement for Coumadin.
Using this novel technique and new anti-platelet regimen , they observed a very low rate of stent thrombosis while reducing complications associated with anti-coagulation and vascular access.
Below is an example of a patient who underwent an ultrasound-guided percutaneous coronary intervention. The RCA has a critical stenosis in the mid-segment.
There is also an anomalous origin of the left circumflex from the right coronary ostium. His RCA had a significant amount of calcium and the balloon angioplasty did not fully open the artery second image. After rotational atherectomy, the stent was deployed and despite an almost perfect result on the angiogram, IVUS demonstrated an incomplete apposition of the stent third image.
The patient underwent high pressure angioplasty using a non-compliant balloon. The following IVUS image demonstrated a fully expanded and apposed stent with final angiogram showing no significant residual stenosis of the RCA.
Thereafter, Plavix or clopidogrel was favored over Ticlid because of better tolerance and decreased risk of neutropenia. Multi center trials clearly demonstrated the benefit of using dual anti-platelet DAPT consisting of aspirin and Plavix as superior to Coumadin or aspirin alone.
We currently follow a patient who underwent coronary stenting of the circumflex coronary artery in the early 90s using the femoral approach. He stayed in the hospital for a week and developed a large groin hematoma that had to be evacuated surgically. He was discharged on aspirin and Coumadin. Fifteen years later, he presented with worsening angina and myocardial ischemia on the thallium stress test.
Coronary arteriogram was scheduled as an outpatient. He underwent percutaneous coronary intervention of his right coronary artery using a radial approach and was discharged the same afternoon on aspirin and Plavix. Results Among patients treated with BMS who were randomized to continued thienopyridine vs placebo, rates of stent thrombosis were 0. Conclusions and Relevance Among patients undergoing coronary stent placement with BMS and who tolerated 12 months of thienopyridine, continuing thienopyridine for an additional 18 months compared with placebo did not result in statistically significant differences in rates of stent thrombosis, MACCE, or moderate or severe bleeding.
However, the BMS subset may have been underpowered to identify such differences, and further trials are suggested. Trial Registration clinicaltrials. Quiz Ref ID Current clinical practice guidelines recommend a minimum of only 1 month of dual antiplatelet therapy DAPT after bare metal stent BMS placement following elective percutaneous coronary intervention PCI , compared with 6 to 12 months for drug-eluting stents DES , 1 , 2 and patients with acute coronary syndromes benefit from 12 months of therapy whether or not PCI with stent placement is performed.
We compared the randomized treatment effect of continuing to receive thienopyridine vs receiving placebo beyond 12 months with regard to stent thrombosis, MACCE, and bleeding after randomization until the completion of study drug treatment at 30 months among patients treated with BMS as well as the combined cohort of patients treated with BMS or DES. As a prespecified analysis, we assessed the consistency of treatment duration effect between patients treated with BMS or DES. The results comparing randomized treatments in the DES-treated cohort have been reported separately.
All institutions received approval from their institutional review boards, and each patient provided written informed consent for study participation. All patients older than 18 years who met all enrollment inclusion and none of the exclusion criteria eTable 1 in the Supplement and signed the consent were enrolled into the trial within 3 days of the index procedure, and all received open-label aspirin plus thienopyridine for the first 12 months.
As permitted by regulatory authorities, race and ethnicity data were collected via patient self-report. Ethnicity was collected as Hispanic or Latino and not Hispanic or Latino. At 12 months, patients who were alive and free from MI, stroke, repeat coronary revascularization, stent thrombosis, and moderate or severe bleeding and who demonstrated adherence with thienopyridine treatment were then eligible for randomization Figure to continue receiving thienopyridine or to receive placebo, and all continued aspirin.
A computer-generated randomization schedule stratified patients according to the type of stent they had received DES vs BMS , hospital site, thienopyridine type, and presence or absence of at least 1 prespecified clinical- or lesion-related risk factor for stent thrombosis eTable 2 in the Supplement. Postrandomization study procedures and follow-up were the same for all patients regardless of whether they had BMS or DES. The co-primary effectiveness end points were cumulative incidence of definite or probable stent thrombosis according to the Academic Research Consortium classification 9 and incidence of MACCE at 12 to 30 months.
Finally, clinically actionable bleeding not related to coronary artery bypass graft procedures was also evaluated according to the Bleeding Academic Research Consortium definitions BARC type 2, 3, or 5. An unblinded independent central data monitoring committee oversaw the safety of all patients. Among patients treated with BMS and randomized to continued thienopyridine vs placebo, the cumulative incidence of stent thrombosis and of MACCE are presented according to intention-to-treat.
Patients not experiencing the co-primary end points at 12 to 30 months after the index procedure were censored at the time of last known contact or 30 months, whichever was earlier.
The analysis of the BMS cohort comparing randomized treatment groups was a prespecified secondary analysis of the DAPT Study that was not powered to compare treatment groups within this cohort the powered DES-treated cohort has been previously presented 4 but was performed to assess consistency of the randomized treatment effect among patients treated with BMS vs DES from the DAPT Study.
All other analyses presented were prespecified. All P values are 2-sided and considered significant at the. Of enrolled patients treated with BMS, The most common reason eligible patients were not randomized was withdrawal of consent. Baseline characteristics of randomized patients treated with BMS were similar between the groups Table 1. While the same inclusion and exclusion criteria were applied to all enrolled patients, DES- and BMS-treated patients differed according to clinical and procedural characteristics eTable 2 in the Supplement.
Patients treated with DES were more likely to have a history of diabetes mellitus The baseline characteristics of the randomized patients treated with DES have been previously published. Severe bleeding was uncommon, fatal bleeding events BARC type 5 were rare, and rates were not different between treatment groups Table 2.
The results comparing continued thienopyridine vs placebo in the cohort treated with DES have been reported previously and demonstrated significant reductions in study co-primary end points of stent thrombosis 0. The prespecified analysis of the effect of continued thienopyridine found nonsignificant interactions between randomized BMS- and DES-treated patients for both stent thrombosis HR, 0.
Among all randomized patients, the co-primary effectiveness end points of stent thrombosis 0. Significant reductions were observed in MI related to stent thrombosis 0. Similarly, BARC type 2, 3, or 5 bleeding events were significantly increased in the continued thienopyridine treatment group 5.
Quiz Ref ID Among patients undergoing coronary stent placement with BMS and who tolerated 12 months of thienopyridine, continuing thienopyridine for an additional 18 months compared with placebo did not result in statistically significant differences in rates of stent thrombosis, MACCE, or moderate or severe bleeding. While fewer patients treated with BMS were enrolled and randomized because of the prevailing use of DES in clinical practice, among patients eligible for continued DAPT, a prespecified analysis found nonsignificant interactions for the effect of continued thienopyridine therapy on stent thrombosis among BMS- and DES-treated patients who were randomized in the DAPT Study.
The largest portion of MI prevented by extended-duration thienopyridine therapy in this study did not involve the stented coronary segments for either DES or BMS. While bleeding events were similarly increased with continued thienopyridine therapy beyond 1 year among both BMS- and DES-treated patients, these events were infrequently severe and rarely fatal BARC type 5.
Quiz Ref ID The lack of apparent treatment interaction between DES and BMS supports the combined analysis of treatment effects of continued duration of therapy independent of stent type.
The major limitation of the BMS randomized comparison of DAPT duration is small sample size and lack of power, which limits the interpretability of the findings. However, an adequately powered randomized BMS cohort would require approximately additional patients, which was practically not feasible. An adequate number of patients treated with BMS were enrolled to allow a powered comparison of stent thrombosis and MACCE rates with patients treated with DES, 8 the results of which have been presented separately.
0コメント