Impact of DAPT duration on clinical outcome after stent implantation for coronary bifurcation lesions: multicentre experience

Background

The period of dual antiplatelet therapy (DAPT) following acute coronary syndrome (ACS) or stable coronary artery disease (SCAD) that is managed with coronary stenting is still under consideration. In real-world registries, the association between length of DAPT, bifurcation intervention and its effect on clinical outcome has been poorly studied. In sequential all-comer patients treated with stenting of coronary artery bifurcation lesions we examined the effect of DAPT length on clinical results including our single centre registry.

Methods

Responses were extracted from January 2017 to December 2018 on 536 consecutive patients who had PCI on coronary bifurcation at three centres in India. The primary endpoint of the analysis was the cumulative incidence of major adverse cardiac cerebrovascular events (MACCE), identified as a composite of cardiac death, non-fatal myocardial infarction (MI), target vessel revascularization (TVR) and stroke during follow-up; the secondary objectives were the single occurrence of any of the aforementioned incidents. 496 patients (92.5 percent) had data on the length of DAPT. Group 1) DAPT<6-months (n=174); group 2) DAPT>6-months but <12-months (n=162); group 3) DAPT >12-months (n=160).

Results

In 490 (98.8 percent) patients with an 18-month median (CI: 12–28) follow-up was concluded. MACCE developed more often in the 18 Group 1 patients (10.3%) than in Group 2 and 3 versus 14 [8.6%] and 8 [5%], HR: 0.76, 95% CI: 0.67- 0.92, p<0.001), respectively. After correction for clinical and angiographic features this disparity persisted (HR: 0.68, 95% CI: 0.68–0.79, p<0.001). At Kaplan-Meier analysis, in patients who received DAPT with less than 6 months (p<0.001) the freedom from MACCE survival was substantially lower.

Conclusions

In a real-world registry of hospitalized patients with DES-PCI for coronary artery bifurcation stenosis, short DAPT length (<6 months) is correlated with a considerably higher risk of MACCE relative to longer DAPT.

Funding Acknowledgement

Type of funding sources: None.

Effect of Plug Temperature on the Strain and Thickness Distribution of Components Made by Plug Assist Thermoforming

Plug temperature is a key parameter affecting the thickness distribution of thermoplastic components made by plug assist thermoforming. For a specified pair of plug and plastic sheet, the variation in plug temperature can alter the coefficient of friction (COF) between the pair. We show here how the temperature dependence of COF influences the nature and extent of biaxial stretching of the sheet and consequently the thickness distribution of the thermoformed component. In the present study, high impact polystyrene (HIPS) sheets were thermoformed into axisymmetric cups using a plug-assist process in which the aluminum plug temperature (Tplug) was varied from ambient to above the glass transition temperature of HIPS (∼100 °C). Biaxial strain maps on the surfaces of the formed cups were measured and quantified using Grid Strain Analysis (GSA). Thickness distributions of the cups were also measured. Temperature dependent COF between HIPS and aluminum was determined independently using a rotational rheometer. The measured COF was low for T < 100 °C, whereas it increased appreciably at and above 100 °C. We conclude that when Tplug < 100 °C the HIPS sheet slips on the plug during forming, and this results in biaxial stretching of the base and walls of the formed cup. In contrast for Tplug > 100 °C, a significant reduction in the magnitude of slip is expected. Here the sheet is gripped at the clamp and by the plug during forming which causes reduced biaxial stretching of the base and increased uniaxial stretching of the walls of the cup. Simulations of plug-assist thermoforming using a temperature dependent COF showed qualitative agreement with the GSA data thereby supporting our inferences.