ABSTRACT
OBJECTIVES: The aim of this study was to investigate the clinical outcomes of patients deferred from coronary revascularization on the basis of instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) measurements in stable angina pectoris (SAP) and acute coronary syndromes (ACS). BACKGROUND: Assessment of coronary stenosis severity with pressure guidewires is recommended to determine the need for myocardial revascularization. METHODS: The safety of deferral of coronary revascularization in the pooled per-protocol population (n = 4,486) of the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) and iFR-SWEDEHEART (Instantaneous Wave-Free Ratio Versus Fractional Flow Reserve in Patients With Stable Angina Pectoris or Acute Coronary Syndrome) randomized clinical trials was investigated. Patients were stratified according to revascularization decision making on the basis of iFR or FFR and to clinical presentation (SAP or ACS). The primary endpoint was major adverse cardiac events (MACE), defined as the composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization at 1 year. RESULTS: Coronary revascularization was deferred in 2,130 patients. Deferral was performed in 1,117 patients (50%) in the iFR group and 1,013 patients (45%) in the FFR group (p < 0.01). At 1 year, the MACE rate in the deferred population was similar between the iFR and FFR groups (4.12% vs. 4.05%; fully adjusted hazard ratio: 1.13; 95% confidence interval: 0.72 to 1.79; p = 0.60). A clinical presentation with ACS was associated with a higher MACE rate compared with SAP in deferred patients (5.91% vs. 3.64% in ACS and SAP, respectively; fully adjusted hazard ratio: 0.61 in favor of SAP; 95% confidence interval: 0.38 to 0.99; p = 0.04). CONCLUSIONS: Overall, deferral of revascularization is equally safe with both iFR and FFR, with a low MACE rate of about 4%. Lesions were more frequently deferred when iFR was used to assess physiological significance. In deferred patients presenting with ACS, the event rate was significantly increased compared with SAP at 1 year.
Subject(s)
Acute Coronary Syndrome/diagnosis , Angina, Stable/diagnosis , Cardiac Catheterization , Coronary Artery Disease/diagnosis , Coronary Stenosis/diagnosis , Fractional Flow Reserve, Myocardial , Myocardial Revascularization , Time-to-Treatment , Acute Coronary Syndrome/physiopathology , Acute Coronary Syndrome/therapy , Aged , Angina, Stable/physiopathology , Angina, Stable/therapy , Clinical Decision-Making , Coronary Artery Disease/physiopathology , Coronary Artery Disease/therapy , Coronary Stenosis/physiopathology , Coronary Stenosis/therapy , Female , Humans , Male , Middle Aged , Myocardial Revascularization/adverse effects , Patient Selection , Predictive Value of Tests , Randomized Controlled Trials as Topic , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
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 .).
Subject(s)
Acute Coronary Syndrome/physiopathology , Angina Pectoris/physiopathology , Coronary Stenosis/physiopathology , Coronary Stenosis/therapy , Fractional Flow Reserve, Myocardial , Percutaneous Coronary Intervention/methods , Acute Coronary Syndrome/diagnostic imaging , Aged , Angina Pectoris/diagnostic imaging , Cardiovascular Diseases/mortality , Coronary Angiography , Coronary Stenosis/complications , Coronary Stenosis/diagnostic imaging , Female , Follow-Up Studies , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myocardial Infarction/epidemiology , Retreatment , Severity of Illness IndexABSTRACT
A lesão da parede arterial provocada por balão de angioplastia ou implante de próteses endovasculares em modelos experimentais e humanos pode provocar a reestenose do vaso, principalmente por migração e proliferação de células musculares lisas e síntese de matriz extracelular. Vários estudos demonstraram que a braquiterapia intra-arterial atua nestes fatores e, conseqüentemente, no tratamento da reestenose coronariana. Este estudo tem por objetivo avaliar as alterações vasculares morfológicas e morfométricas induzidas pela braquiterapia com samário-153 (153Sm), utilizando uma dose considerada ideal e outra elevada em coelhos hipercolesterolêmicos. Foram analisados 43 coelhos hipercolesterolêmicos e um total de 86 artérias ilíacas submetidas à lesão por balão de angioplastia, divididos em três grupos, sendo irradiados com as doses de 15Gy (n = 14) e 60Gy (n = 36) e controle (n = 36). Foram realizadas análise morfométrica (área neo-intimal, área da camada média, área do vaso) e análise histológica qualitativa para avaliação tecidual. O colesterol médio foi de 1.362 ± 497mg/dl nos três grupos. O achado mais relevante foi uma significativa inibição da hiperplasia neo-intimal no grupo irradiado com a dose de 15Gy, maior do que o controle e com a dose de 60Gy. Na dose de 60 Gy, além de ineficaz para inibir a proliferação neo-intimal, teve características tissulares e estruturais sugestivas de radiolesão, como presença de células xantomatosas, tecidos hialino e amorfo, proliferação vascular. Estas células, bem como o aumento das dimensões morfométricas do vaso, foram proporcionais aos graus de lesão nas lâminas elásticas interna e externa, sendo observados principalmente com a dose de 60Gy. Os segmentos médios das artérias ilíacas, representando o local de maior contato com o balão, tiveram maiores alterações morfométricas e celulares em relação aos segmentos referenciais (proximal e distal) nos três grupos. Em conclusão, o grupo de artérias submetidas à irradiação de 15Gy foi eficaz para a inibição da proliferação neo-intimal. O grupo irradiado com a maior dose de 60Gy foi ineficaz para inibir a hiperplasia neo-intimal e apresentou características morfométricas e teciduais compatíveis com a radiolesão vascular.
