Safety and Feasibility Using a Fluid-Filled Wire to Avoid Hydrostatic Errors in Physiological Intracoronary Measurements

Background

Using a fluid-filled wire with a pressure sensor outside the patient compared to a conventional pressure wire may avoid the systematic error introduced by the hydrostatic pressure within the coronary circulation.

Aims

To assess the safety and effectiveness of the novel fluid-filled wire, Wirecath (Cavis Technologies, Uppsala, Sweden), as well as its ability to avoid the hydrostatic pressure error.

Methods and Results

The Wirecath pressure wire was used in 45 eligible patients who underwent invasive coronary angiography and had a clinical indication for invasive coronary pressure measurement at Sahlgrenska University Hospital, Gothenburg, Sweden. In 29 patients, a simultaneous measurement was performed with a conventional coronary pressure wire (PressureWire X, Abbott Medical, Plymouth, MN, USA), and in 19 patients, the vertical height difference between the tip of the guide catheter and the wire measure point was measured in a 90-degree lateral angiographic projection. No adverse events caused by the pressure wires were reported. The mean Pd/Pa and mean FFR using the fluid-filled wire and the sensor-tipped wire differed significantly; however, after correcting for the hydrostatic effect, the sensor-tipped wire pressure correlated well with the fluid-filled wire pressure (R = 0.74 vs. R = 0.89 at rest and R = 0.89 vs. R = 0.98 at hyperemia).

Conclusion

Hydrostatic errors in physiologic measurements can be avoided by using the fluid-filled Wirecath wire, which was safe to use in the present study. This trial is registered with NCT04776577 and NCT04802681.

Characteristics, survival and neurological outcome in out-of-hospital cardiac arrest in young adults in Sweden: A nationwide study

Aim

The aim of this study was to present a comprehensive overview of out-of-hospital cardiac arrests (OHCA) in young adults.

Methods

The data set analyzed included all cases of OHCA from 1990 to 2020 in the age-range 16-49 years in the Swedish Registry of Cardiopulmonary Resuscitation (SRCR). OHCA between 2010 and 2020 were analyzed in more detail. Clinical characteristics, survival, neurological outcomes, and long-time trends in survival were studied. Logistic regression was used to study 30-days survival, neurological outcomes and Utstein determinants of survival.

Results

Trends were assessed in 11,180 cases. The annual increase in 30-days survival during 1990-2020 was 5.9% with no decline in neurological function among survivors. Odds ratio (OR) for heart disease as the cause was 0.55 (95% CI 0.44 to 0.67) in 2017-2020 compared to 1990-1993. Corresponding ORs for overdoses and suicide attempts were 1.61 (95% CI 1.23-2.13) and 2.06 (95% CI 1.48-2.94), respectively. Exercise related OHCA was noted in roughly 5%. OR for bystander CPR in 2017-2020 vs 1990-1993 was 3.11 (95% CI 2.57 to 3.78); in 2020 88 % received bystander CPR. EMS response time increased from 6 to 10 minutes.

Conclusion

Survival has increased 6% annually, resulting in a three-fold increase over 30 years, with stable neurological outcome. EMS response time increased with 66% but the majority now receive bystander CPR. Cardiac arrest due to overdoses and suicide attempts are increasing.

Predicting survival and neurological outcome in out-of-hospital cardiac arrest using machine learning: the SCARS model

BACKGROUND

A prediction model that estimates survival and neurological outcome in out-of-hospital cardiac arrest patients has the potential to improve clinical management in emergency rooms.

METHODS

We used the Swedish Registry for Cardiopulmonary Resuscitation to study all out-of-hospital cardiac arrest (OHCA) cases in Sweden from 2010 to 2020. We had 393 candidate predictors describing the circumstances at cardiac arrest, critical time intervals, patient demographics, initial presentation, spatiotemporal data, socioeconomic status, medications, and comorbidities before arrest. To develop, evaluate and test an array of prediction models, we created stratified (on the outcome measure) random samples of our study population. We created a training set (60% of data), evaluation set (20% of data), and test set (20% of data). We assessed the 30-day survival and cerebral performance category (CPC) score at discharge using several machine learning frameworks with hyperparameter tuning. Parsimonious models with the top 1 to 20 strongest predictors were tested. We calibrated the decision threshold to assess the cut-off yielding 95% sensitivity for survival. The final model was deployed as a web application.

FINDINGS

We included 55,615 cases of OHCA. Initial presentation, prehospital interventions, and critical time intervals variables were the most important. At a sensitivity of 95%, specificity was 89%, positive predictive value 52%, and negative predictive value 99% in test data to predict 30-day survival. The area under the receiver characteristic curve was 0.97 in test data using all 393 predictors or only the ten most important predictors. The final model showed excellent calibration. The web application allowed for near-instantaneous survival calculations.

INTERPRETATION

Thirty-day survival and neurological outcome in OHCA can rapidly and reliably be estimated during ongoing cardiopulmonary resuscitation in the emergency room using a machine learning model incorporating widely available variables.

FUNDING

Swedish Research Council (2019-02019); Swedish state under the agreement between the Swedish government, and the county councils (ALFGBG-971482); The Wallenberg Centre for Molecular and Translational Medicine.

A novel fluid-filled pressure wire avoids hydrostatic errors in physiologic measurements

Background

Hydrostatic pressure impacts intracoronary pressure measurements, generally causing overestimation of stenosis significance in the LAD and underestimation in non-LAD vessels [1–3]. Different cut-offs have been suggested for post-PCI FFR [4], corresponding to average hydrostatic effects [1–3]. Different cut-offs and stenosis misclassification may be avoided if hydrostatic effects are eliminated.

Purpose

We aimed to compare the effect of hydrostatic pressure on resting distal-to-aortic coronary pressure ratio (Pd/Pa) and FFR, using a conventional sensor-tipped- versus a novel fluid-filled pressure wire. Since the fluid-filled wire has an outside-the-body pressure transducer instead of a sensor at the tip, the fluid (saline) compensates for the hydrostatic pressure that is inside the patient's body.

Methods

We placed the sensor of a sensor-tipped wire and the measure point of a fluid-filled wire at the same location in the coronary vessel. By performing simultaneous measurements, we aimed to assess the relationship between vertical height differences and distal pressure (Pd).

We measured the vertical height difference between the tip of the guide catheter and the measure point, by changing the vertical position of the cath lab table and assessing the total distance in mm between the two table positions.

Results

The two wires were used simultaneously in 21 arteries. The lower in the coronary tree the measurements were made (e.g., in the LCX or RCA), the higher the Pd value by the conventional wire was, compared to the novel wire; the higher the measurement was made (e.g., in the LAD), the lower the Pd value.

After we corrected for hydrostatic effect on the sensor-tipped wire using the height measurement (0.77 mmHg/cm [2]), sensor-tipped wire pressure correlated better with fluid-filled wire pressure (R=0.73 vs. R=0.89 at rest and R=0.83 vs. R=0.96 at hyperaemia).

Drift was also compared in 31 simultaneous measurements. The fluid-filled wire demonstrated less drift than the sensor-tipped wire (standard deviation 0.11 vs. 0.18). With an increasing number of cases, less drift was observed, possibly learning curve-related.

Finally, we compared measurements of pressure-derived CFR using the fluid-filled wire, versus echocardiography-CFR (n=10) and bolus thermodilution-CFR (n=11). Pressure-derived CFR with the fluid-filled wire correlated to echocardiography-CFR and thermodilution-CFR (R=0.69 and R=0.76 respectively). Sensor-tipped wire pressure-derived CFR did not correlate to thermodilution-CFR measurements (n=11; R=−0.57).

Conclusions

Hydrostatic pressure introduces a variable error in conventional intracoronary pressure measurements. Resting indices are more susceptible to the hydrostatic error than hyperaemic. There is a slight learning curve associated with use of the novel wire, but hydrostatic errors in physiologic measurements can be avoided thanks to the wire's fluid-filled design and external pressure transducer.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish Governmental Agency for Innovation Systems (Vinnova)

Predicting risk of future acute coronary syndromes, 1-year survival and the need for coronary angiography in unstable angina: a nationwide machine learning study

Background

We developed machine learning models to predict the need for coronary angiography, recurrent acute coronary syndromes (ACS) and 1-year survival in patients with chest pain and normal high-sensitivity troponins. We also studied whether hs-troponin levels within the normal range convey predictive information on these outcomes.

Purpose

We studied whether machine learning could reliably predict survival, risk of future ACS and rule out unnecessary angiographies in patients with chest pain and normal hs-troponins. We aimed to deploy these models as open-sourced web applications, to provide clinicians with individualized predictions. We also studied whether normal hs-troponin levels may serve as predictors of these outcomes.

Methods

We used the SWEDEHEART registry to include patients admitted due to chest pain, with normal high-sensitivity troponin T or I (hs-TnI, hs-TnT), who underwent angiography and did not receive a final diagnosis of acute myocardial infarction. We studied angiographic findings on segmental level, developed machine learning models for future ACS and death (within 1-year, modelled separately) and unnecessary coronary angiography, which was defined as angiography that did not lead to any intervention. Models predicting future ACS and 1-year survival included 130 candidate predictors and models for unnecessary angiography included 110 predictors. We built approximately 50'000 models, using gradient boosting, extreme gradient boosting, random forest, artificial neural networks and logistic regression.

Results

We included 9'314 patients. The 1-year mortality rate was 0.9% (n=78), rate of future ACS was 2.7% (n=251), and rate of unnecessary angiography was 61.5% (n=5455). Up to 40% had normal angiography. There was a strong association between troponin levels (within normal range) and severity of coronary atherosclerosis; e.g 32.4% in patients with hs-TnI 26–35 ng/L had >50% stenosis in segment 6, as compared with 12.6% in those with hs-TnI 0–5 ng/L. All segments displayed similar associations with troponin levels. Mortality increased at hs-TnI levels above 10 ng/L for men, but not women. Age and sex adjusted hazard ratios for hs-TnI 25–35 vs hs-TnI 0–5 was 5.73 (2.14–15.35) for 1-year mortality. The strongest predictors of 1-year mortality were C-reactive protein, body mass index, estimated glomerular filtration rate, age, time from symptom onset to CCU admission, systolic blood pressure and hs-TnI. Extreme gradient boosting was the best performing model for all prediction tasks; AUC ROC in the test data sets were 0.77 for 1-year mortality, 0.77 for future ACS and 0.78 for unnecessary angiography, with excellent calibration.

Conclusion

Machine learning models can reliably predict 1-year risk of death or ACS, as well as predict unnecessary angiographies. Troponin levels within normal range constitute a strong predictor of all these outcomes, questioning the definition of normal troponin.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Sahlgrenska University hospital

Characteristics, survival and neurological outcome in out-of-hospital cardiac arrest: A nationwide study of 56,203 cases with emphasis on cardiovascular comorbidities

Background

We studied clinical characteristics, survival and neurological outcomes in patients with pre-existing cardiovascular (CV) conditions who experienced an out-of-hospital cardiac arrest (OHCA).

Methods

We studied all cases of OHCA in the Swedish Registry for Cardiopulmonary Resuscitation (2010–2020). Patients were grouped according to the following pre-existing CV conditions prior: hypertension (HT), heart failure (HF) with HT, HF with ischemic heart disease (IHD), HF without HT or IHD, IHD, myocardial infarction (MI) and diabetes mellitus (DM), with groups being mutually exclusive. We studied 30-day survival and neurological outcomes using logistic and Cox regression.

Results

A total of 56,203 patients were included. The lowest rates of shockable rhythm occurred in cases with HT (19%), HF and HT (18%) and DM (18%). Median time to OHCA from diagnosis of HT was 2.0 years in cases aged 0–40 years at diagnosis of HT, 4.4 years in those aged 41–60 at diagnosis, 5.0 years in those aged 61–70 years, 5.6 years in those aged 71–80 years and 6.0 years in those aged 81 years or older. The lowest survival was noted for patients with HF and HT. Age and sex adjusted OR for CPC score 1 did not differ in any group.

Conclusion

The combination of HT and HF has the lowest survival of all cardiovascular comorbidities. Early onset of hypertension is a predictor for early cardiac arrest.

Trends in survival after cardiac arrest: a Swedish nationwide study over 30 years

AIMS

Trends in characteristics, management, and survival in out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) were studied in the Swedish Cardiopulmonary Resuscitation Registry (SCRR).

METHODS AND RESULTS

The SCRR was used to study 106 296 cases of OHCA (1990-2020) and 30 032 cases of IHCA (2004-20) in whom resuscitation was attempted. In OHCA, survival increased from 5.7% in 1990 to 10.1% in 2011 and remained unchanged thereafter. Odds ratios [ORs, 95% confidence interval (CI)] for survival in 2017-20 vs. 1990-93 were 2.17 (1.93-2.43) overall, 2.36 (2.07-2.71) for men, and 1.67 (1.34-2.10) for women. Survival increased for all aetiologies, except trauma, suffocation, and drowning. OR for cardiac aetiology in 2017-20 vs. 1990-93 was 0.45 (0.42-0.48). Bystander cardiopulmonary resuscitation increased from 30.9% to 82.2%. Shockable rhythm decreased from 39.5% in 1990 to 17.4% in 2020. Use of targeted temperature management decreased from 42.1% (2010) to 18.2% (2020). In IHCA, OR for survival in 2017-20 vs. 2004-07 was 1.18 (1.06-1.31), showing a non-linear trend with probability of survival increasing by 46.6% during 2011-20. Myocardial ischaemia or infarction as aetiology decreased during 2004-20 from 67.4% to 28.3% [OR 0.30 (0.27-0.34)]. Shockable rhythm decreased from 37.4% to 23.0% [OR 0.57 (0.51-0.64)]. Approximately 90% of survivors (IHCA and OHCA) had no or mild neurological sequelae.

CONCLUSION

Survival increased 2.2-fold in OHCA during 1990-2020 but without any improvement in the final decade, and 1.2-fold in IHCA during 2004-20, with rapid improvement the last decade. Cardiac aetiology and shockable rhythms were halved. Neurological outcome has not improved.

Nationwide observational study of incidence, management and outcome of spontaneous coronary artery dissection: a report from the Swedish Coronary Angiography and Angioplasty register

OBJECTIVES

The aim of this study was to conduct a nationwide all comer description of incidence, contemporary management and outcome in Swedish spontaneous coronary artery dissection (SCAD) patients. The incidence of SCAD as well as the management and outcome of these patients is not well described.

DESIGN

A nationwide observational study.

PARTICIPANTS AND SETTING

All patients with SCAD registered in the Swedish Coronary Angiography and Angioplasty Register from 2015 to 2017 were included. The index angiographies of patients with registered SCAD were re-evaluated at each centre to confirm the diagnosis. Patients with non-SCAD myocardial infarction (MI) (n=32 601) were used for comparison.

OUTCOME MEASURES

Outcomes included all-cause mortality, reinfarction or acute coronary reangiography.

RESULTS

This study found 147 SCAD patients, rendering an incidence of 0.74 per 100 000 per year and a prevalence of 0.43% of all MIs. The average age was 52.9 years, 75.5% were women and 47.6% presented with ST-segment elevation MI. Median follow-up time for major adverse cardiac event was 17.3 months. Percutaneous coronary intervention was attempted in 40.1% of SCAD patients and 30.6% received stent. The use of antithrombotic agents was similar between the groups and there was no difference regarding outcomes, 10.9% vs 13.4%, p=0.75. Mortality was lower in SCAD patients, 2.7% vs 8.0%, p=0.03, whereas SCAD patients more often underwent acute reangiography, 9.5% vs 4.6%, p<0.01.

CONCLUSION

In this nationwide, all comer Swedish study, the overall incidence of SCAD was low, including 25% men which is more and in contrast to previous studies. Compared with non-SCAD MI, SCAD patients were younger, with lower cardiovascular risk burden, yet suffered substantial mortality and morbidity and more frequently underwent acute coronary reangiography.

Cardiorenal Function and Survival in In-Hospital Cardiac Arrest: A Nationwide Study of 22,819 Cases

BACKGROUND

We studied the association between cardiorenal function and survival, neurological outcome and trends in survival after in-hospital cardiac arrest (IHCA).

METHODS

We included cases aged ≥18 years in the Swedish Cardiopulmonary Resuscitation Registry during 2008 to 2020. The CKD-EPI equation was used to calculate estimated glomerular filtration rate (eGFR). A history of heart failure was defined according to contemporary guideline criteria. Logistic regression was used to study survival. Neurological outcome was assessed using cerebral performance category (CPC).

RESULTS

We studied 22,819 patients with IHCA. The 30-day survival was 19.3%, 16.6%, 22.5%, 28.8%, 39.3%, 44.8% and 38.4% in cases with eGFR <15, 15-29, 30-44, 45-59, 60-89, 90-130 and 130-150 ml/min/1.73 m², respectively. All eGFR levels below and above 90 ml/min/1.73 m² were associated with increased mortality. Probability of survival at 30 days was 62% lower in cases with eGFR <15 ml/min/1.73 m², compared with normal kidney function. At every level of eGFR, presence of heart failure increased mortality markedly; patients without heart failure displayed higher mortality only at eGFR below 30 ml/min/1.73 m². Among survivors with eGFR <15 ml/min/1.73 m², good neurological outcome was noted in 87.2%. Survival increased in most groups over time, but most for those with eGFR <15 ml/min/1.73 m², and least for those with normal eGFR.

CONCLUSIONS

All eGFR levels below and above normal range are associated with increased mortality and this association is modified by the presence of heart failure. Neurological outcome is good in the majority of cases, across kidney function levels and survival is increasing.

The incidence, time distribution and prognostic value of monomorphic ventricular tachycardia in ST-elevation myocardial infarction: the prespecified analysis of VALIDATE SWEADHEART trial

Background

The assessment of prognostic impact of ventricular arrhythmias in ST-elevation myocardial infarction (STEMI) is currently based mainly on their timing with regard to the symptom onset and does not distinguish between monomorphic ventricular tachycardia (VT) and polymorphic VT/ventricular fibrillation (VF). However, recent data indicate long-term hazard of monomorphic VT occurring early in the course of STEMI.

Purpose

To evaluate the incidence, time distribution and prognostic value of early monomorphic VT compared to polymorphic VT/VF in STEMI patients treated by primary percutaneous coronary interventions (PCI).

Methods

A prespecified analysis of the multicentre prospective registry-based randomised VALIDATE-SWEDEHEART trial included STEMI patients enrolled at 16 sites in Sweden between June 2014 and September 2016. Source data verification regarding the type and timing of arrhythmia from all patients with VT/VF during STEMI was performed. Survival status was obtained from the Swedish national population registry. Endpoint was total mortality at 180 days.

Results

In total, 2886 patients were identified. Among them, 97 (3.4%) had VF or polymorphic VT, 16 (0.5%) monomorphic VT, 6 (0.2%) had other undefined shockable rhythm. Total mortality (10.9% vs 2.8%, p≤0.001) was higher among patients with VT/VF. VT/VF was associated with total mortality (HR 3.18 95% CI 1.74–5.8; p≤0.001) after adjustment on age, gender and myocardial infarction localisation. In patients discharged from hospital, VT/VF did not influence the long-term prognosis.

Patients with monomorphic VT had similar clinical characteristics as compared to those with polymorphic VT/VF. The time distribution of VT/VF differed with regard to the type of arrhythmia: 63% of monomorphic VT/VF episodes occurred after PCI (n=10) compared to 24% (n=23) of all documented polymorphic VT/VF, p=0.003. Total mortality (12.5% vs 10.3%, p=0.678) did not differ between patients with monomorphic VT and polymorphic VT/VF. In Cox model, total mortality was not associated with the type of arrhythmia (Figure).

Conclusion

Early VT/VF is a marker of poor short-term outcome in patients with STEMI, which does not affect long-term prognosis in those who are successfully resuscitated and discharged from hospital.

The incidence of monomorphic VT in STEMI treated by primary PCI is low, and it occurs mainly after PCI. Though no significant difference in mortality was found between patients with monomorphic VT and polymorphic VT/VF, the observed low incidence hampers drawing conclusions with regard to the prognostic hazard impact of monomorphic VT.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Swedish Heart Lung Foundation

Long-term mortality in patients with ischaemic heart failure revascularized with coronary artery bypass grafting or percutaneous coronary intervention: insights from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

Aims 

To compare coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for treatment of patients with heart failure due to ischaemic heart disease.

Methods and results 

We analysed all-cause mortality following CABG or PCI in patients with heart failure with reduced ejection fraction and multivessel disease (coronary artery stenosis >50% in ≥2 vessels or left main) who underwent coronary angiography between 2000 and 2018 in Sweden. We used a propensity score-adjusted logistic and Cox proportional-hazards regressions and instrumental variable model to adjust for known and unknown confounders. Multilevel modelling was used to adjust for the clustering of observations in a hierarchical database. In total, 2509 patients (82.9% men) were included; 35.8% had diabetes and 34.7% had a previous myocardial infarction. The mean age was 68.1 ± 9.4 years (47.8% were >70 years old), and 64.9% had three-vessel or left main disease. Primary designated therapy was PCI in 56.2% and CABG in 43.8%. Median follow-up time was 3.9 years (range 1 day to 10 years). There were 1010 deaths. Risk of death was lower after CABG than after PCI [odds ratio (OR) 0.62; 95% confidence interval (CI) 0.41–0.96; P = 0.031]. The risk of death increased linearly with quintiles of hospitals in which PCI was the preferred method for revascularization (OR 1.27, 95% CI 1.17–1.38, P  _trend < 0.001).

Conclusion 

In patients with ischaemic heart failure, long-term survival was greater after CABG than after PCI.

Radial artery access is associated with lower mortality in patients undergoing primary PCI: a report from the SWEDEHEART registry

OBJECTIVES

The purpose of this observational study was to evaluate the effects of radial artery access versus femoral artery access on the risk of 30-day mortality, inhospital bleeding and cardiogenic shock in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention.

METHODS

We used data from the SWEDEHEART registry and included all patients who were treated with primary percutaneous coronary intervention in Sweden between 2005 and 2016. We compared patients who had percutaneous coronary intervention by radial access versus femoral access with regard to the primary endpoint of all-cause death within 30 days, using a multilevel propensity score adjusted logistic regression which included hospital as a random effect.

RESULTS

During the study period, 44,804 patients underwent primary percutaneous coronary intervention of whom 24,299 (54.2%) had radial access and 20,505 (45.8%) femoral access. There were 2487 (5.5%) deaths within 30 days, of which 920 (3.8%) occurred in the radial access and 1567 (7.6%) in the femoral access group. After propensity score adjustment, radial access was associated with a lower risk of death (adjusted odds ratio (OR) 0.70, 95% confidence interval (CI) 0.55-0.88, P = 0.025). We found no interaction between access site and age, gender and cardiogenic shock regarding 30-day mortality. Radial access was also associated with a lower adjusted risk of bleeding (adjusted OR 0.45, 95% CI 0.25-0.79, P = 0.006) and cardiogenic shock (adjusted OR 0.41, 95% CI 0.24-0.73, P = 0.002).

CONCLUSIONS

In patients with ST-elevation myocardial infarction, primary percutaneous coronary intervention by radial access rather than femoral access was associated with an adjusted lower risk of death, bleeding and cardiogenic shock. Our findings are consistent with, and add external validity to, recent randomised trials.

Comparative Effectiveness of CABG versus PCI in Patients with Ischemic Heart Disease: insights from SWEDEHEART Registry

Background

Several studies have compared CABG to PCI as revascularization treatment in patients with ischemic heart disease (IHD). However, it remains unclear which revascularization strategy carries survival benefits in the long-term.

Methods

We used data from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry for all hospital admissions at 13 cardiac care centers within Västra Götaland County in Sweden (∼20% of all SWEDEHEART data). The database contains &gt;1000 clinical variables documenting the entire process of acute coronary hospital care. All patients hospitalized for stable angina or NSTE-ACS during the period 2000–2018 were included in the analysis. We used a propensity score-adjusted Cox proportional-hazards regression with hospitals as random-effect variables. We adjusted for patients' demographics, socio-economic status, traditional risk factors, comorbidities, the severity of coronary artery disease, left ventricular function, calendar year and medication at discharge. For sensitivity analysis, we used the instrumental variable estimator for the Cox proportional-hazards model (with treating hospital as a treatment-preference instrument) to simultaneously deal with the problems of unmeasured confounding and censoring of the outcome. The primary outcome was all-cause mortality.

Results

In total, 11,896 patients were included in the study. Of these, 3,129 (26.3%) were women. 20.4% had diabetes and 10.4% had a previous myocardial infarction. The mean age was 66.7±10.7, and 42.9% were &gt;70 years old. 61.5% had three-vessel and/or left main disease. Median follow-up time was 5.7 years (range 1 day-18.2 years). Revascularization therapy after coronary angiography was PCI in 9449 (79.4%) and CABG in 2,447 (20.6%) patients. CABG patients were more likely to have diabetes, left main/multivessel disease and heart failure. The number of revascularized patients with PCI increased by 6.4% per calendar year (P&lt;0.001). There were 2,481 (20.9%) deaths. CABG was associated with a lower risk of death compared to PCI (HR 0.81; 95% CI 0.69–0.95; P=0.011. We found no evidence for treatment heterogeneity between the revascularization strategy and age, gender, diabetes, heart failure and indication for revascularization (all P-interaction &gt;0.05). Results from the sensitivity analysis support the conclusions from the primary model.

Conclusions

In hospitalized patients due to IHD, revascularization with CABG was associated with superior long-term survival compared to PCI.

Funding Acknowledgement

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

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&lt;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

Association of Pretreatment With P2Y12 Receptor Antagonists Preceding Percutaneous Coronary Intervention in Non-ST-Segment Elevation Acute Coronary Syndromes With Outcomes

IMPORTANCE

Pretreatment of patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) with P2Y12 receptor antagonists is a common practice despite the lack of definite evidence for its benefit.

OBJECTIVE

To investigate the association of P2Y12 receptor antagonist pretreatment vs no pretreatment with mortality, stent thrombosis, and in-hospital bleeding in patients with NSTE-ACS undergoing percutaneous coronary intervention (PCI).

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used prospective data from the Swedish Coronary Angiography and Angioplasty Registry of 64 857 patients who underwent procedures between 2010 and 2018. All patients who underwent PCI owing to NSTE-ACS in Sweden were stratified by whether they were pretreated with P2Y12 receptor antagonists. Associations of pretreatment with P2Y12 receptor antagonists with the risks of adverse outcomes were investigated using instrumental variable analysis and propensity score matching. Data were analyzed from March to June 2019.

EXPOSURES

Pretreatment with P2Y12 receptor antagonists.

MAIN OUTCOMES AND MEASURES

The primary end point was all-cause mortality within 30 days. Secondary end points were 1-year mortality, stent thrombosis within 30 days, and in-hospital bleeding.

RESULTS

In total, 64 857 patients (mean [SD] age, 64.7 [10.9] years; 46 809 [72.2%] men) were included. A total of 59 894 patients (92.4%) were pretreated with a P2Y12 receptor antagonist, including 27 867 (43.7%) pretreated with clopidogrel, 34 785 (54.5%) pretreated with ticagrelor, and 1148 (1.8%) pretreated with prasugrel. At 30 days, there were 971 deaths (1.5%) and 101 definite stent thromboses (0.2%) in the full cohort. Pretreatment was not associated with better survival at 30 days (odds ratio [OR], 1.17; 95% CI, 0.66-2.11; P = .58), survival at 1 year (OR, 1.34; 95% CI, 0.77-2.34; P = .30), or decreased stent thrombosis (OR, 0.81; 95% CI, 0.42-1.55; P = .52). However, pretreatment was associated with increased risk of in-hospital bleeding (OR, 1.49; 95% CI, 1.06-2.12; P = .02).

CONCLUSIONS AND RELEVANCE

This cohort study found that pretreatment of patients with NSTE-ACS with P2Y12 receptor antagonists was not associated with improved clinical outcomes but was associated with increased risk of bleeding. These findings support the argument that pretreatment with P2Y12 receptor antagonists should not be routinely used in patients with NSTE-ACS.

Ticagrelor is Not Superior to Clopidogrel in Patients With Acute Coronary Syndromes Undergoing PCI: A Report from Swedish Coronary Angiography and Angioplasty Registry

Background

Ticagrelor reduces ischaemic end points in acute coronary syndromes. However, outcomes of ticagrelor versus clopidogrel in real‐world patients with acute coronary syndromes treated with percutaneous coronary intervention (PCI) remain unclear. We sought to examine whether treatment with ticagrelor is superior to clopidogrel in unselected patients with acute coronary syndromes treated with PCI.

Methods and Results

We used data from SCAAR (Swedish Coronary Angiography and Angioplasty Registry) for PCI performed in Västra Götaland County, Sweden. The database contains information about all PCI performed at 5 hospitals (∼20% of all data in SCAAR). All procedures between January 2005 and January 2015 for unstable angina/non‒ST‐segment‒elevation myocardial infarction and ST‐segment‒elevation myocardial infarction were included. We used instrumental variable 2‐stage least squares regression to adjust for confounders. The primary combined end point was mortality or stent thrombosis at 30 days, secondary end points were mortality at 30 days and 1‐year, stent thrombosis at 30 days, in‐hospital bleeding, in‐hospital neurologic complications and long‐term mortality. A total of 15 097 patients were included in the study of which 2929 (19.4%) were treated with ticagrelor. Treatment with ticagrelor was not associated with a lower risk for the primary end point (adjusted odds ratio [aOR], 1.20; 95% CI, 0.87–1.61; P=0.250). Estimated risk of death at 30 days (aOR, 1.18; 95% CI, 0.88–1.64; P=0.287) and at 1‐year (aOR, 1.28; 95% CI, 0.86–1.64; P=0.556) was not different between the groups. The risk of in‐hospital bleeding was higher with ticagrelor (aOR, 2.88; 95% CI, 1.53–5.44; P=0.001).

Conclusions

In this observational study, treatment with ticagrelor was not superior to clopidogrel in patients with acute coronary syndromes treated with PCI.

Prognostic impact of percutaneous coronary intervention in octogenarians with non-ST elevation myocardial infarction: A report from SWEDEHEART

AIMS

Percutaneous coronary intervention (PCI) improves outcomes in non-ST elevation acute coronary syndromes (NSTE-ACSs). Octogenarians, however, were underrepresented in the pivotal trials. This study aimed to assess the effect of PCI in patients ≥80 years old.

METHODS AND RESULTS

We used data from the SWEDEHEART registry for all hospital admissions at eight cardiac care centres within Västra Götaland County. Consecutive patients ≥80 years old admitted for NSTE-ACS between January 2000 and December 2011 were included. We performed instrumental variable analysis with propensity score. The primary endpoint was all-cause mortality at 30 days and one year after index hospitalization. During the study period 5200 patients fulfilled the inclusion criteria. In total, 586 (11.2%) patients underwent PCI, the remaining 4613 patients were treated conservatively. Total mortality at 30 days was 19.4% (1007 events) and 39.4% (1876 events) at one year. Thirty-day mortality was 20.7% in conservatively treated patients and 8.5% in the PCI group (adjusted odds ratio 0.34; 95% confidence interval 0.12-0.97, p = 0.044). One-year mortality was 42.1% in the conservatively treated group and 16.3% in the PCI group (adjusted odds ratio 0.97; 95% confidence interval 0.36-2.51, p = 0.847).

CONCLUSIONS

PCI in octogenarians with NSTE-ACS was associated with a lower risk of mortality at 30 days. However, this survival benefit was not sustained during the entire study-period of one-year.

Prognostic Impact of Chronic Total Occlusions: A Report From SCAAR (Swedish Coronary Angiography and Angioplasty Registry)

OBJECTIVES

The aim of this study was to determine the prognostic impact of chronic total occlusion (CTO) on long-term mortality in a large prospective cohort.

BACKGROUND

CTO is present in many patients with coronary artery disease and is difficult to treat with percutaneous coronary intervention.

METHODS

The study population consisted of all consecutive patients who underwent coronary angiography in Sweden between January 1, 2005 and January 1, 2012, who were registered in SCAAR (Swedish Coronary Angiography and Angioplasty Registry). The patient population was heterogeneous with regard to indication for angiography (stable angina, ST-segment elevation myocardial infarction [STEMI], unstable angina or non-STEMI, and other) and treatment options. The long-term mortality rates of patients with and without CTO were compared by using shared frailty Cox proportional hazards regression adjusted for confounders. Tests were conducted for interactions between CTO and several pre-specified characteristics: indication for angiography and percutaneous coronary intervention (stable angina, STEMI, unstable angina or non-STEMI, and other), severity of coronary artery disease (1-, 2-, and 3-vessel and/or left main coronary artery disease), age, sex, and diabetes.

RESULTS

During the study period, 14,441 patients with CTO and 75,431 patients without CTO were registered in SCAAR. CTO was associated with higher mortality (hazard ratio: 1.29; 95% confidence interval: 1.22 to 1.37; p < 0.001). In subgroup analyses, the risk attributable to CTO was lowest in patients with stable angina and highest in those with STEMI. In addition, CTO was associated with highest risk in patients under 60 years of age and with lowest risk in octogenarians. There was no interaction between CTO and either diabetes or sex, suggesting an equally adverse effect in both groups.

CONCLUSIONS

In this large prospective observational study of patients with coronary artery disease, CTO was associated with increased mortality. This association was most prominent in younger patients and in those with acute coronary syndromes.

Hypertension is associated with increased mortality in patients with ischaemic heart disease after revascularization with percutaneous coronary intervention - a report from SCAAR

BACKGROUND

The prognostic role of hypertension on long-term survival after percutaneous coronary intervention (PCI) is limited and inconsistent. We hypothesize that hypertension increases long-term mortality after PCI.

METHODS

We analyzed data from SCAAR (Swedish Coronary Angiography and Angioplasty Registry) for all consecutive patients admitted coronary care units in Sweden between January 1995 and May 2013 and who underwent PCI due to ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI)/unstable angina (UA) or stable angina pectoris. We used Cox proportional-hazards regression for statistical modelling on complete-case data as well as on imputed data sets. We used interaction test to evaluate possible effect-modulation of hypertension on risk estimates in several pre-specified subgroups: age categories, gender, diabetes, smoking and indication for PCI (STEMI, NSTEMI/UA and stable angina).

RESULTS

During the study period, 175,892 consecutive patients underwent coronary angiography due to STEMI, NSTEMI/UA or stable angina. 78,100 (44%) of these had hypertension. Median follow-up was 5.5 years. After adjustment for differences in patient's characteristics, hypertension was associated with increased risk for mortality (HR 1.12, 95% CI 1.09-1.15, p < .001). In subgroup analysis, risk was highest in patients less than 65 years, in smokers and in patients with STEMI. The risk was lowest in patients with stable angina (p < .001 for interaction test).

CONCLUSION

Hypertension is associated with higher mortality in patients with STEMI, NSTEMI/UA or stable angina who are treated with PCI.

Trends in Gender Differences in Cardiac Care and Outcome After Acute Myocardial Infarction in Western Sweden: A Report From the Swedish Web System for Enhancement of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART)

BACKGROUND

Cardiovascular disease is the most common cause of death for both genders. Debates are ongoing as to whether gender-specific differences in clinical course, diagnosis, and management of acute myocardial infarction (MI) exist.

METHODS AND RESULTS

We compared all men and women who were treated for acute MI at cardiac care units in Västra Götaland, Sweden, between January 1995 and October 2014 by obtaining data from the prospective SWEDEHEART (Swedish Web-System for Enhancement of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry. We performed unadjusted and adjusted Cox proportional hazards and logistic regression analyses on complete case data and on imputed data sets. Overall, 48 118 patients (35.4% women) were diagnosed with acute MI. Women as a group had better age-adjusted prognosis than men, but this survival benefit was absent for younger women (aged <60 years) and for women with ST-segment elevation MI. Compared with men, younger women and women with ST-segment elevation MI were more likely to develop prehospital cardiogenic shock (adjusted odds ratio 1.67, 95% CI 1.30 to 2.16, P<0.001 and adjusted odds ratio 1.31, 95% CI 1.16 to 1.48, P<0.001) and were less likely to be prescribed evidence-based treatment at discharge (P<0.001 for β-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, statins, and P2Y12 antagonists). Differences in treatment between the genders did not decrease over the study period (P>0.1 for all treatments).

CONCLUSIONS

Women on average have better adjusted prognosis than men after acute MI; however, younger women and women with ST-segment elevation MI have disproportionately poor prognosis and are less likely to be prescribed evidence-based treatment.

Low socioeconomic status of a patient's residential area is associated with worse prognosis after acute myocardial infarction in Sweden

INTRODUCTION

Previous studies have established a relationship between socioeconomic status (SES) and survival in coronary heart disease. Acute cardiac care in Sweden is considered to be excellent and independent of SES. We studied the influence of area-level socioeconomic status on mortality after hospitalization for acute myocardial infarction (AMI) between 1995 and 2013 in the Gothenburg metropolitan area, which has little over 800,000 inhabitants and includes three city hospitals.

METHODS

Data were obtained from the SWEDEHEART registry (Swedish Websystem for Enhancement of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) and the Swedish Central Bureau of Statistics for patients hospitalized for ST-elevation myocardial infarction (STEMI) and non-STEMI in the city of Gothenburg in Western Sweden. The groups were compared using Cox proportional hazards regression and logistic regression.

RESULTS

10,895 (36% female) patients were hospitalized due to AMI during the study period. Patients residing in areas with lower SES had higher rates of smoking and diabetes (P<0.001), and were also at increased risk of developing complications, including heart failure and cardiogenic shock (P<0.05). Living in an area with lower SES associated with increased risk of dying after an AMI also in models adjusted for risk factors (P<0.05).

CONCLUSION

Also in a country with strong egalitarian traditions, lower SES associates with worse prognosis after AMI, an association that persists after adjustments for differences in traditional cardiovascular risk factors.

Chronic total occlusions in Sweden--a report from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

INTRODUCTION

Evidence for the current guidelines for the treatment of patients with chronic total occlusions (CTO) in coronary arteries is limited. In this study we identified all CTO patients registered in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) and studied the prevalence, patient characteristics and treatment decisions for CTO in Sweden.

METHODS AND RESULTS

Between January 2005 and January 2012, 276,931 procedures (coronary angiography or percutaneous coronary intervention) were performed in 215,836 patients registered in SCAAR. We identified all patients who had 100% luminal diameter stenosis known or assumed to be ≥ 3 months old. After exclusion of patients with previous coronary artery bypass graft (CABG) surgery or coronary occlusions due to acute coronary syndrome, we identified 16,818 CTO patients. A CTO was present in 10.9% of all coronary angiographies and in 16.0% of patients with coronary artery disease. The majority of CTO patients were treated conservatively and PCI of CTO accounted for only 5.8% of all PCI procedures. CTO patients with diabetes and multivessel disease were more likely to be referred to CABG.

CONCLUSION

CTO is a common finding in Swedish patients undergoing coronary angiography but the number of CTO procedures in Sweden is low. Patients with CTO are a high-risk subgroup of patients with coronary artery disease. SCAAR has the largest register of CTO patients and therefore may be valuable for studies of clinical importance of CTO and optimal treatment for CTO patients.

Successful percutaneous coronary intervention during cardiac arrest with use of an automated chest compression device: a case report

Ventricular tachycardia or fibrillation (VT/VF) in patients with ST-elevation myocardial infarction (STEMI) is associated with poor prognosis. Performing manual chest compressions is a serious obstacle for treatment with percutaneous coronary intervention (PCI). Here we introduce a case with refractory VT/VF where the patient was successfully treated with an automated chest compression device, which made revascularization with PCI possible.

Does the timing of treatment with intra-aortic balloon counterpulsation in cardiogenic shock due to ST-elevation myocardial infarction affect survival?

BACKGROUND

Intra-aortic balloon pump (IABP) counterpulsation and primary percutaneous coronary intervention (PCI) are standard treatment modalities in cardiogenic shock (CS) complicating acute myocardial infarction. The aim of this study was to investigate the impact of the timing of IABP treatment start in relation to PCI procedure.

METHODS

Data were obtained from the SCAAR registry (Swedish Coronary Angiography and Angioplasty Registry) about 139 consecutive patients with CS due to ST-elevation myocardial infarction (STEMI) who received IABP treatment. The patients were hospitalized at Sahlgrenska University Hospital, Gothenburg, during 2004-2008. The cohort was divided into the two groups: group (A) in whom IABP treatment started before start of PCI (n = 72) and group (B) in whom IABP treatment started after PCI treatment (n = 67). The primary endpoint was 30-day mortality. Propensity score (PS) adjusted Cox proportional hazards regression was used to analyze predictors of 30-day mortality.

RESULTS

Mean age was 66.5 ± 12 and 28% were women. All patients have received IABP treatment 30 min before or 30 min after primary PCI. 63% had diabetes and 28% had hypertension. 16% were active tobacco smokers. The mortality rate at 30 days was 38%. IABP treatment commenced before or after PCI was not an independent predictor of mortality (P = 0.72).

CONCLUSION

In this non-randomized trial the treatment with insertion of IABP before primary PCI in patients with CS due to STEMI is not associated with a more favorable outcome as compared with IABP started after primary PCI.

Immunoenzymatic detection of the new proliferation associated protein p100 by means of a cellular ELISA: specific detection of cells in cell cycle phases S, G2 and M

In vitro proliferation assays are widely used in biomedical research. We describe the immunoenzymatic (ELISA) detection of a recently described proliferation associated protein (p100) by means of a new monoclonal mouse IgG1 antibody (Ki-S2). P100 is a 100 kDa nuclear protein that is specifically detected during the cell cycle phases S, G2 and M. Comparative studies on lectin-stimulated leukocytes using 3H-thymidine labelling and Ki-67 antibodies revealed a statistically significant positive correlation. Since p100 is absent in GO and G1 cells, its detection permits the precise and specific measurement of actual cell cycle events under culture conditions.

Improved ELISA proliferation assay (EPA) for the detection of in vitro cell proliferation by a new Ki-67-antigen directed monoclonal antibody (Ki-S3)

We describe a simplified and improved proliferation assay based on a conventional ELISA system for the in vitro measurement of cellular proliferation (ELISA proliferation assay = EPA). The assay is based on a new monoclonal antibody (Ki-S3) to the proliferation-specific Ki-67-antigen and is carried out in 96-well microtiter plates using conventional immunoenzymatic methods. Ki-S3 is an immunoprecipitating monoclonal mouse IgG1 antibody, which recognizes a formalin-resistant epitope of the Ki-67 antigen. It can be used to measure proliferating cells in the cell cycle phases G1, S, G2 and M. In phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) the absorbance values obtained with the EPA show a statistically significant correlation to the number of Ki-S3 positive cells in simultaneously immunostained cytospin slides (r = 0.88). A direct comparison with [3H]thymidine labeling reveals the test to be an equally sensitive method for monitoring cellular proliferation (r = 0.91). This assay is an improved ELISA proliferation assay, which is easy to perform, does not require time-consuming pretreatments and avoids the hazards of radioactive isotopes.