The exercise pressor reflex and changes in radial arterial pressure and heart rate during walking in patients with arteriosclerosis obliterans

Little is known about the time course and extent of the changes in radial arterial pressure and heart rate taking place in patients with arteriosclerosis obliterans during walking, as well their subtending mechanisms. For this reason the authors measured these variables in 23 patients with arteriosclerosis obliterans and in nine normal subjects (control group), during treadmill walking and several tests. In the patients a rapid and marked increase in radial arterial pressure was recorded during walking, whereas the same parameter either fell abruptly or persisted at elevated levels during recovery. This pattern markedly differed from that recorded in normal subjects, and it was mainly brought about by the activation of the exercise pressor reflex. The following findings suggested that the exercise pressor reflex was activated: the conditions required for activation of the reflex were present in our patients; the pressure changes observed during walking tightly paralleled the changes due to this reflex activation; the hypertensive response to walking was enhanced by increases in severity of disease and in walking speed and duration; the reflex activity persisted during recovery; and the pressure pattern during walking was reproduced by walking with arrested blood circulation to a lower limb. On the contrary, the behavior of heart rate was similar in patients and normal subjects both during walking and recovery because it was not influenced by the exercise pressor reflex

Impact of Sex on Comparative Outcomes of Radial Versus Femoral Access in Patients With Acute Coronary Syndromes Undergoing Invasive Management: Data From the Randomized MATRIX-Access Trial

Objectives This study sought to assess whether transradial access (TRA) compared with transfemoral access (TFA) is associated with consistent outcomes in male and female patients with acute coronary syndrome undergoing invasive management. Background There are limited and contrasting data about sex disparities for the safety and efficacy of TRA versus TFA for coronary intervention. Methods In the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) program, 8,404 patients were randomized to TRA or TFA. The 30-day coprimary outcomes were major adverse cardiovascular and cerebrovascular events (MACCE), defined as death, myocardial infarction, or stroke, and net adverse clinical events (NACE), defined as MACCE or major bleeding. Results Among 8,404 patients, 2,232 (26.6%) were women and 6,172 (73.4%) were men. MACCE and NACE were not significantly different between men and women after adjustment, but women had higher risk of access site bleeding (male vs. female rate ratio [RR]: 0.64; p = 0.0016), severe bleeding (RR: 0.17; p = 0.0012), and transfusion (RR: 0.56; p = 0.0089). When comparing radial versus femoral, there was no significant interaction for MACCE and NACE stratified by sex (p int = 0.15 and 0.18, respectively), although for both coprimary endpoints the benefit with TRA was relatively greater in women (RR: 0.73; p = 0.019; and RR: 0.73; p = 0.012, respectively). Similarly, there was no significant interaction between male and female patients for the individual endpoints of all-cause death (p int = 0.79), myocardial infarction (p int = 0.25), stroke (p int = 0.18), and Bleeding Academic Research Consortium type 3 or 5 (p int = 0.45). Conclusions Women showed a higher risk of severe bleeding and access site complications, and radial access was an effective method to reduce these complications as well as composite ischemic and ischemic or bleeding endpoints

Assessment of residual thrombus burden in patients with ST-segment elevation myocardial infarction undergoing bivalirudin versus unfractionated heparin infusion: The MATRIX (minimizing adverse hemorrhagic events by transradial access site and angioX) OCT study

Background: Residual stent strut thrombosis after primary percutaneous coronary intervention (PCI), negatively affects myocardial perfusion, may increase stent thrombosis risk, and it is associated with neointima hyperplasia at follow-up. Objectives: To study the effectiveness of any bivalirudin infusion versus unfractionated heparin (UFH) infusion in reducing residual stent strut thrombosis in patients with ST-elevation myocardial infarction (STEMI). Methods: Multi-vessel STEMI patients undergoing primary PCI and requiring staged intervention were selected among those randomly allocated to two different bivalirudin infusion regimens in the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) Treatment-Duration study. Those receiving heparin only were enrolled into a registry arm. Optical coherence tomography (OCT) of the infarct-related artery was performed at the end of primary PCI and 3–5 days thereafter during a staged intervention. The primary endpoint was the change in minimum flow area (ΔMinFA) defined as (stent area + incomplete stent apposition [ISA] area) − (intraluminal defect + tissue prolapsed area) between the index and staged PCI. Results: 123 patients in bivalirudin arm and 28 patients in the UFH arm were included. Mean stent area, percentage of malapposed struts, and mean percent thrombotic area were comparable after index or staged PCI. The ΔMinFA in the bivalirudin group was 0.25 versus 0.05 mm2 in the UFH group, which resulted in a between-group significant difference of 0.36 [95% CI: (0.05, 0.71); p =.02]. This was mostly related to a decrease in tissue protrusion in the bivalirudin group (p =.03). There was a trend towards more patients in the bivalirudin group who achieved a 5% difference in the percentage of OCT frames with the area >5% (p =.057). Conclusions: The administration of bivalirudin after primary PCI significantly reduces residual stent strut thrombosis when compared to UFH. This observation should be considered hypothesis-generating since the heparin-treated patients were not randomly allocated

Impact of optical coherence tomography findings on clinical outcomes in ST-segment elevation myocardial infarction patients: a MATRIX (Minimizing Adverse Hemorrhagic Events by Trans-radial Access Site and angioX) OCT sub-study

Purpose: To investigate the association of the degree of stent expansion, as assessed by optical coherence tomography (OCT), following stent implantation, and clinical outcomes in ST-segment elevation myocardial infarction (STEMI) patients. Methods: STEMI patients from the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) OCT study were selected; Clinical outcomes were collected through 1 year. Stent expansion index is a minimum stent area (MSA) divided by average lumen area (average of proximal and distal reference lumen area). The following variables were measured: MSA (< 4.5mm2), dissection (> 200 µm in width and < 5 mm from stent segment), malapposition (> 200 µm distance of stent from vessel wall), a thrombus (area > 5% of lumen area) were compared. Results: A total of 151 patients were included; after excluding patients with suboptimal OCT quality, the population with available OCT was classified into 2 groups: under–expanded < 90% (N = 72, 51%) and well–expanded ≥ 90% (N = 67, 49%). In the well–expanded group, a significant number of the proximal vessels had a lumen area < 4.5mm2 (16.1%, p < 0.001) and a greater thrombus burden within stent (56.7%, p = 0.042). The overall 30 day and 1 year major adverse cardiovascular event (MACE) rates were 5% and 6.1%, respectively. Conclusion: Irrespective of the degree of stent expansion, the OCT findings, in STEMI patients, and the MACE at 30 days and one year follow up was low; further, well–expanded stents led to a more significant residual thrombotic burden within the stent but seemed to have insignificant clinical impact. Acknowledged stent optimization criteria, traditionally related to worse outcomes in stable patients, do not seem to be associated with worse outcomes in this STEMI population

Bivalirudin or Heparin in Patients Undergoing Invasive Management of Acute Coronary Syndromes

Background: Contrasting evidence exists on the comparative efficacy and safety of bivalirudin and unfractionated heparin (UFH) in relation to the planned use of glycoprotein IIb/IIIa inhibitors (GPIs). Objectives: This study assessed the efficacy and safety of bivalirudin compared with UFH with or without GPIs in patients with acute coronary syndrome (ACS) who underwent invasive management. Methods: In the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX) program, 7,213 patients were randomly assigned to receive either bivalirudin or UFH with or without GPIs at discretion of the operator. The 30-day coprimary outcomes were major adverse cardiovascular events (MACEs) (a composite of death, myocardial infarction, or stroke), and net adverse clinical events (NACEs) (a composite of MACEs or major bleeding). Results: Among 3,603 patients assigned to receive UFH, 781 (21.7%) underwent planned treatment with GPI before coronary intervention. Bailout use of GPIs was similar between the bivalirudin and UFH groups (4.5% and 5.4%) (p = 0.11). At 30 days, the 2 coprimary endpoints of MACEs and NACEs, as well as individual endpoints of mortality, myocardial infarction, stent thrombosis or stroke did not differ among the 3 groups after adjustment. Compared with the UFH and UFH+GPI groups, bivalirudin reduced bleeding, mainly the most severe bleeds, including fatal and nonaccess site−related events, as well as transfusion rates and the need for surgical access site repair. These findings were not influenced by the administered intraprocedural dose of UFH and were confirmed at multiple sensitivity analyses, including the randomly allocated access site. Conclusions: In patients with ACS, the rates of MACEs and NACEs were not significantly lower with bivalirudin than with UFH, irrespective of planned GPI use. However, bivalirudin significantly reduced bleeding complications, mainly those not related to access site, irrespective of planned use of GPIs. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX [MATRIX]; NCT01433627