Instantaneous Wave-free Ratio versus Fractional Flow Reserve to Guide PCI.

BACKGROUND: The instantaneous wave-free ratio (iFR) is an index used to assess the severity of coronary-artery stenosis. The index has been tested against fractional flow reserve (FFR) in small trials, and the two measures have been found to have similar diagnostic accuracy. However, studies of clinical outcomes associated with the use of iFR are lacking. We aimed to evaluate whether iFR is noninferior to FFR with respect to the rate of subsequent major adverse cardiac events. METHODS: We conducted a multicenter, randomized, controlled, open-label clinical trial using the Swedish Coronary Angiography and Angioplasty Registry for enrollment. A total of 2037 participants with stable angina or an acute coronary syndrome who had an indication for physiologically guided assessment of coronary-artery stenosis were randomly assigned to undergo revascularization guided by either iFR or FFR. The primary end point was the rate of a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization within 12 months after the procedure. RESULTS: A primary end-point event occurred in 68 of 1012 patients (6.7%) in the iFR group and in 61 of 1007 (6.1%) in the FFR group (difference in event rates, 0.7 percentage points; 95% confidence interval [CI], -1.5 to 2.8; P=0.007 for noninferiority; hazard ratio, 1.12; 95% CI, 0.79 to 1.58; P=0.53); the upper limit of the 95% confidence interval for the difference in event rates fell within the prespecified noninferiority margin of 3.2 percentage points. The results were similar among major subgroups. The rates of myocardial infarction, target-lesion revascularization, restenosis, and stent thrombosis did not differ significantly between the two groups. A significantly higher proportion of patients in the FFR group than in the iFR group reported chest discomfort during the procedure. CONCLUSIONS: Among patients with stable angina or an acute coronary syndrome, an iFR-guided revascularization strategy was noninferior to an FFR-guided revascularization strategy with respect to the rate of major adverse cardiac events at 12 months. (Funded by Philips Volcano; iFR SWEDEHEART ClinicalTrials.gov number, NCT02166736 .).

Thrombus aspiration during ST-segment elevation myocardial infarction.

BACKGROUND: The clinical effect of routine intracoronary thrombus aspiration before primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is uncertain. We aimed to evaluate whether thrombus aspiration reduces mortality. METHODS: We conducted a multicenter, prospective, randomized, controlled, open-label clinical trial, with enrollment of patients from the national comprehensive Swedish Coronary Angiography and Angioplasty Registry (SCAAR) and end points evaluated through national registries. A total of 7244 patients with STEMI undergoing PCI were randomly assigned to manual thrombus aspiration followed by PCI or to PCI only. The primary end point was all-cause mortality at 30 days. RESULTS: No patients were lost to follow-up. Death from any cause occurred in 2.8% of the patients in the thrombus-aspiration group (103 of 3621), as compared with 3.0% in the PCI-only group (110 of 3623) (hazard ratio, 0.94; 95% confidence interval [CI], 0.72 to 1.22; P=0.63). The rates of hospitalization for recurrent myocardial infarction at 30 days were 0.5% and 0.9% in the two groups, respectively (hazard ratio, 0.61; 95% CI, 0.34 to 1.07; P=0.09), and the rates of stent thrombosis were 0.2% and 0.5%, respectively (hazard ratio, 0.47; 95% CI, 0.20 to 1.02; P=0.06). There were no significant differences between the groups with respect to the rate of stroke or neurologic complications at the time of discharge (P=0.87). The results were consistent across all major prespecified subgroups, including subgroups defined according to thrombus burden and coronary flow before PCI. CONCLUSIONS: Routine thrombus aspiration before PCI as compared with PCI alone did not reduce 30-day mortality among patients with STEMI. (Funded by the Swedish Research Council and others; ClinicalTrials.gov number, NCT01093404.).

Instantaneous Wave-Free Ratio versus Fractional Flow Reserve guided intervention (iFR-SWEDEHEART): Rationale and design of a multicenter, prospective, registry-based randomized clinical trial.

BACKGROUND: Instantaneous wave-free ratio (iFR) is a new hemodynamic resting index for assessment of coronary artery stenosis severity. iFR uses high frequency sampling to calculate a gradient across a coronary lesion during a period of diastole. The index has been tested against fractional flow reserve (FFR) and found to have an overall classification agreement of 80% to 85%. Whether the level of disagreement is clinically relevant is unknown. Clinical outcome data on iFR are scarce. This study is a registry-based randomized clinical trial, which is a novel strategy using health quality registries as on-line platforms for randomization, case record forms, and follow-up. DESIGN/METHODS: iFR-SWEDEHEART is a multicenter, prospective, randomized, controlled, clinical open-label clinical trial. Two thousand patients with stable angina or acute coronary syndrome and an indication for physiology-guided assessment of one or more coronary stenoses will be randomized 1:1 to either iFR- or FFR-guided intervention. The randomization will be conducted online in the Swedish web-based system for enhancement and development of evidence-based care in heart disease evaluated according to recommended therapies (SWEDEHEART) registry. The trial has a non-inferiority design, with a primary combined end point of all-cause death, non-fatal myocardial infarction, and unplanned revascularization at 12 months. End points will be identified through national registries and undergo central blind adjudication to ensure data quality. DISCUSSION: The iFR-SWEDEHEART trial is an registry-based randomized clinical trial evaluating the safety and efficacy of the diagnostic method iFR compared to FFR.

5-Year Outcomes of PCI Guided by Measurement of Instantaneous Wave-Free Ratio Versus Fractional Flow Reserve.

BACKGROUND: Instantaneous wave-free ratio (iFR) is a coronary physiology index used to assess the severity of coronary artery stenosis to guide revascularization. iFR has previously demonstrated noninferior short-term outcome compared to fractional flow reserve (FFR), but data on longer-term outcome have been lacking. OBJECTIVES: The purpose of this study was to investigate the prespecified 5-year follow-up of the primary composite outcome of all-cause mortality, myocardial infarction, and unplanned revascularization of the iFR-SWEDEHEART trial comparing iFR vs FFR in patients with chronic and acute coronary syndromes. METHODS: iFR-SWEDEHEART was a multicenter, controlled, open-label, registry-based randomized clinical trial using the Swedish Coronary Angiography and Angioplasty Registry for enrollment. A total of 2,037 patients were randomized to undergo revascularization guided by iFR or FFR. RESULTS: No patients were lost to follow-up. At 5 years, the rate of the primary composite endpoint was 21.5% in the iFR group and 19.9% in the FFR group (HR: 1.09; 95% CI: 0.90-1.33). The rates of all-cause death (9.4% vs 7.9%; HR: 1.20; 95% CI: 0.89-1.62), nonfatal myocardial infarction (5.7% vs 5.8%; HR: 1.00; 95% CI: 0.70-1.44), and unplanned revascularization (11.6% vs 11.3%; HR: 1.02; 95% CI: 0.79-1.32) were also not different between the 2 groups. The outcomes were consistent across prespecified subgroups. CONCLUSIONS: In patients with chronic or acute coronary syndromes, an iFR-guided revascularization strategy was associated with no difference in the 5-year composite outcome of death, myocardial infarction, and unplanned revascularization compared with an FFR-guided revascularization strategy. (Evaluation of iFR vs FFR in Stable Angina or Acute Coronary Syndrome [iFR SWEDEHEART]; NCT02166736).

Reclassification of Treatment Strategy With Instantaneous Wave-Free Ratio and Fractional Flow Reserve: A Substudy From the iFR-SWEDEHEART Trial.

OBJECTIVES: The authors sought to compare reclassification of treatment strategy following instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR). BACKGROUND: iFR was noninferior to FFR in 2 large randomized controlled trials in guiding coronary revascularization. Reclassification of treatment strategy by FFR is well-studied, but similar reports on iFR are lacking. METHODS: The iFR-SWEDEHEART (Instantaneous Wave-Free Ratio Versus Fractional Flow Reserve in Patients With Stable Angina Pectoris or Acute Coronary Syndrome Trial) study randomized 2,037 participants with stable angina or acute coronary syndrome to treatment guided by iFR or FFR. Interventionalists entered the preferred treatment (optimal medical therapy [OMT], percutaneous coronary intervention [PCI], or coronary artery bypass grafting [CABG]) on the basis of coronary angiograms, and the final treatment decision was mandated by the iFR/FFR measurements. RESULTS: In the iFR/FFR (n = 1,009/n = 1,004) populations, angiogram-based treatment approaches were similar (p = 0.50) with respect to OMT (38%/35%), PCI of 1 (37%/39%), 2 (15%/16%), and 3 vessels (2%/2%) and CABG (8%/8%). iFR and FFR reclassified 40% and 41% of patients, respectively (p = 0.78). The majority of reclassifications were conversion of PCI to OMT in both the iFR/FFR groups (31.4%/29.0%). Reclassification increased with increasing number of lesions evaluated (odds ratio per evaluated lesion for FFR: 1.46 [95% confidence interval: 1.22 to 1.76] vs. iFR 1.37 [95% confidence interval: 1.18 to 1.59]). Reclassification rates for patients with 1, 2, and 3 assessed vessels were 36%, 52%, and 53% (p < 0.01). CONCLUSIONS: Reclassification of treatment strategy of intermediate lesions was common and occurred in 40% of patients with iFR or FFR. The most frequent reclassification was conversion from PCI to OMT regardless of physiology modality. Irrespective of the physiological index reclassification of angiogram-based treatment strategy increased with the number of lesions evaluated.

Successful resuscitation with mechanical CPR, therapeutic hypothermia and coronary intervention during manual CPR after out-of-hospital cardiac arrest.

A 62-year-old man suffered out-of-hospital cardiac arrest and was treated with mechanical compression-decompression during transport to the hospital. In the emergency department, 28 min after cardiac arrest, spontaneous circulation returned briefly but the patient rapidly became asystolic and mechanical compression-decompression was again applied. After further resuscitation a spontaneous circulation returned and the patient was transferred, deeply comatose, to the coronary intervention laboratory while therapeutic hypothermia was induced. In the laboratory the heart arrested again and coronary angiography was performed during manual CPR revealing a left main stem occlusion. After successful reperfusion of the heart the patient was transferred to the intensive care unit with an intra-aortic balloon pump. The patient was treated with hypothermia for 24 h and awoke without neurological sequelae after a sustained intensive care period of 13 days. The present case is an example of how modern resuscitation principles implementing new clinical and experimental findings may strengthen the chain of survival during resuscitation.

Thrombotic occlusion of all left coronary branches in a young woman with severe ulcerative colitis.

Background. The thrombosis risk is increased in active ulcerative colitis. The limited number of reported complications have predominantly been cerebrovascular but other vessel territories may also be affected. Patient. During a severe attack of ulcerative colitis a 37-year-old woman suffered occlusion of all left coronary artery branches. Serial angiographies showed progressive recanalisation of the coronary arteries during anticoagulation, but no atherosclerotic stenosis. The cause of infarction was thus considered to be an extensive coronary thrombosis. However, a large battery of blood tests failed to identify any procoagulant abnormality. Conclusion. Evidence is now accumulating that the increased thrombosis risk also may involve the coronary arteries, even in young patients. To the best of our knowledge this is the third reported case of myocardial infarction despite angiographically normal coronary arteries in a patient with active ulcerative colitis. The extent of affected myocardium was in this case exceptionally large.