The relationship between procedural volume and patient outcomes for percutaneous coronary interventions: a systematic review and meta-analysis

BACKGROUND

The relationship between procedural volume and outcomes for percutaneous coronary interventions (PCI) is contentious, with previous reviews suggesting an inverse volume-outcome relationship. The aim of this study was to systematically review contemporary evidence to re-examine this relationship.

METHODS

A systematic review and meta-analysis was undertaken to examine the relationship between PCI procedural volume (both at hospital- and operator-levels) and outcomes in adults. The primary outcome was mortality. The secondary outcomes were complications, healthcare utilisation and process outcomes. Searches were conducted from 1 January 2008 to 28 May 2019. Certainty of the evidence was assessed using 'Grading of Recommendations, Assessment, Development and Evaluations' (GRADE). Screening, data extraction, quality appraisal and GRADE assessments were conducted independently by two reviewers.

RESULTS

Of 1,154 unique records retrieved, 22 observational studies with 6,432,265 patients were included. No significant association was found between total PCI hospital volume and mortality (odds ratio [OR]: 0.84, 95% confidence interval [CI]: 0.69-1.03, I 2 = 86%). A temporal trend from significant to non-significant pooled effect estimates was observed. The pooled effect estimate for mortality was found to be significantly in favour of high-volume operators for total PCI procedures (OR: 0.77, 95% CI: 0.63-0.94, I 2 = 93%), and for high-volume hospitals for primary PCI procedures (OR: 0.77, 95% CI: 0.62-0.94, I 2 = 78%). Overall, GRADE certainty of evidence was 'very low'. There were mixed findings for secondary outcomes.

CONCLUSIONS

A volume-outcome relationship may exist in certain situations, although this relationship appears to be attenuating with time, and there is 'very low' certainty of evidence. While volume might be important, it should not be the only standard used to define an acceptable PCI service and a broader evaluation of quality metrics should be considered that encompass patient experience and clinical outcomes. Systematic review registration: PROSPERO, CRD42019125288.

Impact of Hospital Volume of Percutaneous Coronary Intervention (PCI) on In-Hospital Outcomes in Patients with Acute Myocardial Infarction: Based on the 2014 Cohort of the Korean Percutaneous Coronary Intervention (K-PCI) Registry

BACKGROUND AND OBJECTIVES

The relationship between the hospital percutaneous coronary intervention (PCI) volumes and the in-hospital clinical outcomes of patients with acute myocardial infarction (AMI) remains the subject of debate. This study aimed to determine whether the in-hospital clinical outcomes of patients with AMI in Korea are significantly associated with hospital PCI volumes.

METHODS

We selected and analyzed 17,121 cases of AMI, that is, 8,839 cases of non-ST-segment elevation myocardial infarction and 8,282 cases of ST-segment elevation myocardial infarction, enrolled in the 2014 Korean percutaneous coronary intervention (K-PCI) registry. Patients were divided into 2 groups according to hospital annual PCI volume, that is, to a high-volume group (≥400/year) or a low-volume group (<400/year). Major adverse cardiovascular and cerebrovascular events (MACCEs) were defined as composites of death, cardiac death, non-fatal myocardial infarction (MI), stent thrombosis, stroke, and need for urgent PCI during index admission after PCI.

RESULTS

Rates of MACCE and non-fatal MI were higher in the low-volume group than in the high-volume group (MACCE: 10.9% vs. 8.6%, p=0.001; non-fatal MI: 4.8% vs. 2.6%, p=0.001, respectively). Multivariate regression analysis showed PCI volume did not independently predict MACCE.

CONCLUSIONS

Hospital PCI volume was not found to be an independent predictor of in-hospital clinical outcomes in patients with AMI included in the 2014 K-PCI registry.

Differences of in-hospital outcomes within patients undergoing percutaneous coronary intervention at institutions with high versus low procedural volume: a report from the Japanese multicentre percutaneous coronary intervention registry

Objective

We aimed to determine the relationship between the prevalence of in-hospital complications and annual institutional patient volume in a population of patients undergoing percutaneous coronary intervention (PCI).

Methods

Clinical data of patients receiving PCI between January 2010 and June 2015 were collected from 14 academic institutions in the Tokyo area and subsequently used for analysis. We employed multivariate hierarchical logistic regression models to determine the effect of institutional volume on several in-hospital outcomes, including in-hospital mortality and procedure-related complications.

Results

A total of 14 437 PCI cases were included and categorised as receiving intervention from either lower-volume (<200 procedures/year, n=6 hospitals) or higher-volume (≥200 procedures/year, n=8 hospitals) institutions. Clinical characteristics differed significantly between the two patient groups. Specifically, patients treated in higher-volume hospitals presented with increased comorbidities and complex coronary lesions. Unadjusted mortality and complication rate in lower-volume and higher-volume hospitals were 1.3% and 1.2% (p=0.0614) and 6.2% and 8.1% (p=0.001), respectively. However, multivariate hierarchical logistic regression models adjusting for differences in the patient characteristics demonstrated that institutional volume was not associated with adverse clinical outcomes.

Conclusions

In conclusion, we observed no significant association between annual institutional volume and in-hospital outcomes within the contemporary PCI multicentre registry.

Trial registration number

UMIN R000005598.

Total Center Percutaneous Coronary Intervention Volume and 30-Day Mortality: A Contemporary National Cohort Study of 427 467 Elective, Urgent, and Emergency Cases

BACKGROUND

The relationship between procedural volume and prognosis after percutaneous coronary intervention (PCI) remains uncertain, with some studies finding in favor of an inverse association and some against. This UK study provides a contemporary reassessment in one of the few countries in the world with a nationally representative PCI registry.

METHODS AND RESULTS

A nationwide cohort study was performed using the national British Cardiovascular Intervention Society registry. All adult patients undergoing PCI in 93 English and Welsh NHS hospitals between 2007 and 2013 were analyzed using hierarchical modeling with adjustment for patient risk. Of 427 467 procedures (22.0% primary PCI) in 93 hospitals, 30-day mortality was 1.9% (4.8% primary PCI). 87.1% of centers undertook between 200 and 2000 procedures annually. Case mix varied with center volume. In centers with 200 to 399 PCI cases per year, a smaller proportion were PCI for ST-segment-elevation myocardial infarction (8.4%) than in centers with 1500 to 1999 PCI cases per year (24.2%), but proportionally more were for ST-segment-elevation myocardial infarction with cardiogenic shock (8.4% versus 4.3%). For the overall PCI cohort, after risk adjustment, there was no significant evidence of worse, or better, outcomes in lower volume centers from our own study, or in combination with results from other studies. For primary PCI, there was also no evidence for increased or decreased mortality in lower volume centers.

CONCLUSIONS

After adjustment for differences in case mix and clinical presentation, this study supports the conclusion of no trend for increased mortality in lower volume centers for PCI in the UK healthcare system.

CLINICAL TRIAL REGISTRATION

https://www.clinicaltrials.gov. Unique identifier: NCT02184949.

Analysis of the Clinical Characteristics, Management, and Causes of Death in Patients with ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention from 2005 to 2014

It is unknown whether there has been any change in the causes of death for acute ST-segment elevation myocardial infarction (STEMI) in the era of aggressive reperfusion. We analyzed the direct causes of in-hospital death in patients with STEMI treated with primary percutaneous coronary intervention (PCI) in a tertiary referral center over the past 10 years.We retrospectively analyzed 878 STEMI patients treated with primary PCI in our hospital between January 2005 and December 2014. There were no significant changes in the age and sex of patients, but the prevalence of hypertension and smoking decreased. STEMI severity increased with more patients in Killip classification > 2. The number of out-ofhospital cardiac arrest events also increased over the 10 years. Symptom onset-to-door time did not change in the 10year study period. The care quality was improved with shorter door-to-balloon time for primary PCI and increased use of dual antiplatelet therapy. The all-cause in-hospital mortality was 9.1%, which did not vary over the 10 years. Multivariable analysis showed that Killip classification > 2 was the most important determinant of death. Cardiogenic shock was the major cause of cardiovascular death. There was an increase in non-cardiovascular causes of death in the most recent 3 years, with infection being a major problem.Despite improvement in care quality for STEMI, the in-hospital mortality did not decrease in this tertiary referral center over these 10 years due to increased disease severity and non-cardiovascular causes of death.

A Systematic Review and Meta-Analysis of the Relationship Between Hospital Volume and the Outcomes of Percutaneous Coronary Intervention

Previous reviews have suggested that hospital volume is inversely related to in-hospital mortality. However, percutaneous coronary intervention (PCI) practices have changed substantially in recent years, and whether this relationship persists remains controversial.A systematic search was performed using PubMed, Embase, and the Cochrane Library to identify studies that describe the effect of hospital volume on the outcomes of PCI. Critical appraisals of the methodological quality and the risk of bias were conducted independently by 2 authors. Fourteen of 96 potentiality relevant articles were included in the analysis. Twelve of the articles described the relationship between hospital volume and mortality and included data regarding odds ratios (ORs); 3 studies described the relationship between hospital volume and long-term survival, and only 1 study included data regarding hazard ratios (HRs). A meta-analysis of postoperative mortality was performed using a random effects model, and the pooled effect estimate was significantly in favor of high volume providers (OR: 0.79; 95% confidence interval [CI], 0.72-0.86; P < 0.001). A systematic review of long-term survival was performed, and a trend toward better long-term survival in high volume hospitals was observed.This meta-analysis only included studies published after 2006 and revealed that postoperative mortality following PCI correlates significantly and inversely with hospital volume. However, the magnitude of the effect of volume on long-term survival is difficult to assess. Additional research is necessary to confirm our findings and to elucidate the mechanism underlying the volume-outcome relationship.

Effects of cardiologist experience on outcomes of patients with ST-elevated myocardial infarction treated with primary PCI in a local area in Japan

Primary percutaneous coronary intervention (PCI) for ST-elevated myocardial infarction (STEMI) results in dramatically improved clinical outcomes when performed in a timely manner. Although guidelines for STEMI patients recommend PCI should be performed by experienced operators with acceptable PCI volume, cardiologists in a local area must perform primary PCI at their own hospitals. This study evaluated the effects of cardiologist experience on outcomes for STEMI patients in a local area in Japan.Between April 2007 and March 2010, 140 consecutive STEMI patients were admitted to our hospital and 121 of these patients received primary PCI. STEMI patients undergoing primary PCI were divided into two groups according to the operator's experience as a cardiologist. We retrospectively analyzed their clinical backgrounds, PCI findings, in-hospital outcomes, and drug administration at discharge.There were no significant differences in any clinical characteristics, angiographic findings, or PCI procedures between the two groups. Clinical outcomes of the two groups were similar, except for the length of hospital stay (21.1 ± 5.8 versus 15.5 ± 9.7; P = 0.0255). The frequency of administration of drugs such as β-blockers (59.1% versus 34.0%; P = 0.0086), aldosterone blockade (10.4% versus 25.5%; P = 0.0334), and nicorandil (76.1% versus 25.5%; P = < 0.0001) was different between the two groups.The clinical outcomes of STEMI patients in this study were satisfactory and almost equivalent when compared according to the experience of the attending cardiologist. The present findings suggest the important clinical implication that younger cardiologists who have experienced PCI procedures to a certain extent can safely perform primary PCI and contribute to better prognoses of STEMI patients.

Regional impact of cardiac arrest center criteria on out-of-hospital transportation practices

BACKGROUND

Cardiac arrest center (CAC) criteria are not well defined, nor is their potential impact on current emergency medical services (EMS) transportation practices for post-cardiac arrest (PCA) patients. In addition to the availability of emergent cardiac catheterization (CATH) and therapeutic hypothermia (TH), high-volume centers and those with PCA protocols have been associated with improved outcomes. Objectives. This study aimed 1) to identify the PCA treatment capabilities of receiving hospitals in a 10-county regional EMS system without official CAC designation and 2) to determine the proportion of PCA patients who are transported to hospitals meeting three proposed CAC definitions. We hypothesized that a majority of patients are already transported to hospitals that meet proposed CAC criteria.

METHODS

We distributed a survey to 34 receiving hospitals to determine availability and volume of CATH, TH, a PCA protocol, and a 24-hour intensivist. We conducted a retrospective study of adult, nontrauma cardiac arrest patients transported with a pulse from 2006 to 2008 for 16 EMS agencies. The proportions of patients transported to hospitals meeting three CAC criteria were compared: criteria A (availability of CATH and TH), criteria B (criteria A, >200 CATHs per year, and a PCA protocol), and criteria C (criteria B and a 24-hour intensivist).

RESULTS

Data were obtained from 31 of 34 hospitals (91.1%), of which 10 (32.3%) met criteria A, seven (22.6%) met criteria B, and six (19.4%) met criteria C. Of 1,193 cardiac arrest patients, 46 (3.9%) were excluded because of transport to a pediatric, closed, or out-of-region hospital. There were 335 patients (81.1%) with return of spontaneous circulation and a pulse present upon arrival at the destination facility transported to hospitals meeting criteria A, 304 patients (73.6%) transported to hospitals meeting criteria B, and 273 patients (66.1%) transported to hospitals meeting criteria C.

CONCLUSIONS

In a region without official CAC designation, only one-third of hospitals meet basic CAC criteria (CATH and TH), but those facilities receive 81% of PCA patients. Fewer patients (66%) are transported to hospitals meeting more stringent CAC criteria. These data describe the potential impact of developing a CAC policy based on current transportation practices.

Upstream vs deferred administration of small-molecule glycoprotein IIb/IIIa inhibitors in primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: insights from randomized clinical trials

BACKGROUND

Recent data have demonstrated similar outcomes for patients with ST-segment elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI) and are treated with small-molecule glycoprotein IIb/IIIa inhibitors (smGPIs) compared with those treated with abciximab. In the present study, a meta-analysis was performed to evaluate the relative safety and efficacy of upstream vs deferred administration of smGPIs in STEMI patients.

METHODS AND RESULTS

A total of 10 randomized clinical trials comparing upstream vs deferred administration of smGPIs in 2,724 patients were located in the electronic databases of the published literature. Preprocedural Thrombolysis In Myocardial Infarction Study (TIMI) grade 2 or 3 flow was present in 45.0% of the upstream group compared with 36.9% in the deferred group (odds ratio (OR) 1.40, P<0.001). However, no difference in post-procedural TIMI 3 flow (OR 0.87, P=0.25) was found between the groups. The 30-day mortality rate in the upstream group did not differ from that of the deferred group (OR 1.04, P=0.85). No significant difference was noted with respect to major bleeding complications (OR 1.25, P=0.38).

CONCLUSIONS

In STEMI patients scheduled for primary PCI, although early smGPIs treatment improved initial epicardial patency, no beneficial effect on post-procedural angiographic or 30-day clinical outcome was found. Thus, the current available data do not support the routine utilization of upstream smGPIs in STEMI patients treated with primary PCI.