Heparin pre-treatment in patients with ST elevation myocardial infarction: a cohort study investigating the effects on coronary artery occlusion, mortality, and bleeding

Background

Unfractionated heparin (UFH) is often administered before arrival at the cath lab in patients with ST-elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI). However, large studies regarding the clinical impacts of UFH pre-treatment are scarce.

Purpose

To investigate if pre-treatment with heparin affects total coronary artery occlusion at angiography, mortality at 30 days, and major bleeding during hospitalization in patients with STEMI undergoing primary PCI.

Methods

The study population was extracted from the SCAAR (Swedish Coronary Angiography and Angioplasty Registry) and consisted of unique patients with a first STEMI event undergoing PCI during the study period 2008 to 2016. Patients receiving UFH pre-treatment were compared with patients not receiving UFH pre-treatment. To obtain relative risks of the outcomes adjusted Poisson regression models with robust standard errors were used. In the adjusted models, we included age, sex, smoking status, year, comorbidities (as specified under tables 1 and 2), and anti-thrombotic treatment (as specified under tables 1 and 2). To obtain absolute risk differences, analyses of propensity score (PS) matched groups were performed. PS was based on the same variables as in the adjusted Poisson regression, and a caliper of 0.02 was used.

Results

A total of 41,631 patients were included in the study population (median age: 67 years; 71% male), with 16,026 receiving pre-treatment with UFH and 25,605 not receiving UFH pre-treatment. The adjusted Poisson model revealed that UFH pre-treatment was associated with an 11% relative risk reduction of coronary artery occlusion (95% confidence interval (CI): 9%; 12%), and an 13% (95% CI: 2%; 23%) reduced relative risk of mortality. For bleeding, no statistically significant difference was found. In the PS-matched analysis (median age: 67 years, 71% male), the absolute risk differences were for coronary artery occlusion 8.3% (95% CI: 7.1%; 9.5%) in favour of UFH pre-treatment, and for mortality 0.5% (−0.1%; 1.2%), with a modest trend in favour of UFH pre-treatment. For bleeding, no statistically significant difference was found.

Conclusion

UFH pre-treatment was associated with a reduction in coronary artery occlusion at presentation at the cath lab in patients with STEMI, the number needed to treat being 13, without increasing the risk of bleeding. Regarding mortality, a reduced relative risk was found in the adjusted regression analysis, but the absolute risk difference was small and not statistically significant in the PS-matched analysis. Due to the retrospective study design, residual confounding cannot be excluded.

Funding Acknowledgement

Type of funding sources: None.

Long-term survival in patients with coronary artery disease undergoing percutaneous coronary intervention with or without intracoronary pressure wire guidance: a report from SCAAR

Background

Intracoronary pressure wire measurements of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) provide decision-making guidance during percutaneous coronary intervention (PCI). However, limited data exist on the impact of FFR/iFR on long-term clinical outcomes in patients with stable angina, unstable angina (UA)/non-ST-segment elevation myocardial infarction (NSTEMI), or STEMI.

Methods

We used data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) on all patients in Sweden undergoing PCI (with or without FFR/iFR guidance) for stable angina, UA/NSTEMI, or STEMI between January 2005 and March 2018. The primary endpoint was all-cause mortality and the secondary endpoints were stent thrombosis or restenosis and periprocedural complications. The primary model was multilevel Cox proportional-hazards regression using an instrumental variable (IV) to adjust for known and unknown confounders with treating hospital as a treatment-preference instrument. The following variables were entered into Cox proportional-hazards regression in addition to the IV: age, sex, diabetes, indication for PCI, severity of coronary disease, smoking status, hypertension, hyperlipidemia, previous myocardial infarction, previous PCI, previous coronary artery bypass graft, type of stent.

Results

In total, 151,001 patients underwent PCI: 31,514 (20.9%) for stable angina, 74,982 (49.6%) for UA/NSTEMI, and 44,505 (29.5%) for STEMI. Of these, FFR/iFR guidance was used in 11,433 patients (7.6%): 5029 (44.0%) with stable angina, 5989 (52.4%) with UA/NSTEMI, and 415 (3.6%) with STEMI; iFR was used in 1156 (10.1%) of these patients. After a median follow-up of 1784 (range 1–4824) days, the FFR/iFR group had lower adjusted risk estimates for all-cause mortality [hazard ratio (HR) 0.79; 95% confidence interval (CI) 0.69–0.91; P=0.001] and stent thrombosis and restenosis (HR 0.13; 95% CI 0.09–0.19; P<0.001). The number of periprocedural complications did not differ significantly between the groups (odds ratio 0.69; 95% CI 0.30–1.55; P=0.368). There was no interaction between FFR/iFR and indication for PCI. We found no difference between FFR and iFR (HR 1.12; 95% CI 0.90–1.59; P=0.216).

Conclusions

In this observational study, the use of FFR/IFR was associated with a lower risk of long-term mortality in patients undergoing PCI for stable angina, UA/NSTEMI, or STEMI. Our study supports the current European and American guidelines for the use of FFR/iFR during PCI and shows that intracoronary pressure wire guidance has prognostic benefit in patients with stable angina as well as in patients with the acute coronary syndrome.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Heart and Lung Foundation, ALF Västra Götaland, Swedish Scientific Council

Utilization and outcomes of rotational atherectomy in Sweden

Aim

To evaluate utilization and outcomes of rotational atherectomy (RA) using data from the Swedish Coronary and Angioplasty Registry (SCAAR)

Methods

We included 1476 patients with 2218 lesions who underwent RA from 2005 to 2016. To study temporal changes, the study period was divided into three equal time-periods, period A, B and C.

Results

Although the number of RA procedures increased 3-fold from 2005 to 2016, the rate of RA (of all PCI procedures) remained low (0.5% vs 1.2% in 2005 vs 2016). RA patients consisted a high-risk group, with advanced age and clustering of comorbidities. Over time, included patients were older and had a higher risk profile. Trans-radial access, drug eluting stent (DES) use and use of intravascular imaging significantly increased from period A to C whereas positioning of a temporary pacemaker or intra-aortic balloon pump declined. Unfractionated heparin became the main anticoagulant (52 vs 87%) and use of glycoprotein IIb/IIIa inhibitors declined (31 vs 12%, in period A vs C). Following RA, 11% of lesions were treated without stent (15 vs 15 vs 8%, in period A, B and C) (Rota-only). In lesions treated with a stent, a bare metal stent (BMS) was implanted in 39% vs 12% vs 2% and a new generation DES (N-DES) in 5 vs 75 vs 97% (period A vs B vs C) of lesions.

The 3-year cumulative rate of restenosis was 6.7% (122 events), (11.1 vs 7.1 vs 4.1% in period A vs B vs C). As compared to DES, rota-only (adjusted HR 2.71; 95% CI 1.69- 4.36) and BMS (adjusted HR 3.63; 95% CI 2.27- 5.81) were associated with significantly higher risk for restenosis. First generation DES were associated with numerically higher but not significantly different risk for restenosis as compared to N-DES (adjusted HR 1.31; 95% CI 0.74- 2.31).

The 3 year cumulative rate of major adverse cardiac events (MACE), including death, myocardial infarction (MI) or any restenosis was 30.6% (34.2 vs 31.4 vs 28.2%, in period A vs B vs C) and the corresponding numbers for all-cause mortality were 18.1% (18.9 vs 18.4 vs 17.0%). After adjustment for baseline characteristics and angiographic findings, RA in period A was associated with higher risk for MACE as compared to period C (adjusted HR 1.40; 95% CI 1.09- 1.79), due to higher risk for MI and restenosis. The difference disappeared when procedural characteristics, including DES use, were added to the model.

The rate of major in-hospital complications was 7.0%, including in-hospital death 1.3%, periprocedural MI 2.8%, perforation 1.1%, cardiac tamponade 0.7%, stroke 0.2% and major bleedings 2.1%. We found no significant differences over time.

Conclusion

During the studied period, RA remained a rare procedure, utilised in a highly selected population. Over time a declining rate of restenosis and MI after RA was observed, a finding that appeared to be mainly driven by an increased use of DES. The rate of major in-hospital complication remained low.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Boston Scientific International