A review of disparities in peripheral artery disease and diabetes-related amputations during the COVID-19 pandemic.

The COVID-19 pandemic has profoundly affected health care delivery. In addition to the significant morbidity and mortality associated with acute illness from COVID-19, the indirect impact has been far-reaching, including substantial disruptions in chronic disease care. As a result of pandemic disruptions in health care, vulnerable and minority populations have faced health inequalities. The aim of this review was to investigate how the COVID-19 pandemic has impacted vulnerable populations with limb-threatening peripheral artery disease and diabetic foot infections.

Lysophosphatidic acid causes endothelial dysfunction in porcine coronary arteries and human coronary artery endothelial cells.

AIM: The objective of this study was to determine the effects of lysophosphatidic acid (LPA) on endothelial functions and molecular alternations in both porcine coronary arteries and human coronary artery endothelial cells (HCAECs). METHODS AND RESULTS: The vessel rings and HCAECs were treated with clinically relevant concentrations of LPA for different times. Vasomotor reactivity was studied with a myograph tension system. LPA (10 and 50 µM) treatment for the vessel rings significantly reduced endothelium-dependent vasorelaxation in response to bradykinin (×10(-5)M) by 32% and 49%, respectively, compared with the control (P<0.05). LPA decreased endothelial nitric oxide synthase (eNOS) mRNA and immunoreactivity levels in the vessel rings. In HCAECs, LPA reduced eNOS mRNA, phospho-eNOS and total eNOS protein levels. In addition, superoxide anion levels in LPA-treated vessel rings and HCAECs were significantly increased by lucegenin-enhanced chemiluminescence assay and dihydroethidium staining, respectively. Mitochondrial membrane potential and ATP content in LPA-treated HCAECs were substantially decreased. The mRNA levels of reactive oxygen species generating enzymes NOX4 and p40(phox) were increased, while endogenous antioxidant enzyme superoxide dismutase 1 was decreased in response to LPA treatment in HCAECs. Furthermore, exogenous antioxidant molecule selenomethionine (SeMet) effectively reversed these LPA-induced effects in both porcine coronary arteries and HCAECs. CONCLUSIONS: LPA causes endothelial dysfunction by a mechanism associated with decreased eNOS expression and increased oxidative stress in porcine coronary arteries and HCAECs.

Catheter-directed thrombectomy and thrombolysis for symptomatic lower-extremity deep vein thrombosis: review of current interventional treatment strategies.

Deep vein thromboses (DVT) along with its clinical sequelae represent a major health care challenge in our society. An acute massive DVT can result in pulmonary embolism resulting in sudden death. Although oral or systemic anticoagulation therapy may minimize thrombus propagation, it remains ineffective in removing thrombus burden and consequently does not prevent postthrombotic syndrome. Recent advances in catheter-based interventions have led to the development of a variety of minimally invasive endovascular strategies to remove venous thrombi. These technologies use various principles, including catheter-directed thrombolytic infusion, rheolytic thrombectomy, mechanical fragmentation, or ultrasound energy to remove intraluminal thrombi. This article reviews the current advances in this technology and discusses the techniques of percutaneous treatment strategies of venous thrombotic conditions using various devices, including the AngioJet Power Pulse system, Trellis, and ultrasound-accelerated EkoSonic system. Finally, the authors' institutional experiences using these interventional treatment strategies in patients with acute and chronic DVT are discussed.

Nerve and conduction tissue injury caused by contact with BioGlue.

BACKGROUND: BioGlue-a surgical adhesive composed of bovine albumin and glutaraldehyde-is commonly used in cardiovascular operations. The objectives of this study were to determine whether BioGlue injures nerves and cardiac conduction tissues, and whether a water-soluble gel barrier protects against such injury. MATERIALS AND METHODS: In 18 pigs, diaphragmatic excursion during direct phrenic nerve stimulation was measured at baseline and at 3 and 30 min after nerve exposure to albumin (n = 3), glutaraldehyde (n = 3), BioGlue (n = 6), or water-soluble gel followed by BioGlue (n = 6). Additionally, BioGlue was applied to the cavoatrial junction overlying the sinoatrial node (SAN), either alone (n = 12) or after application of gel (n = 6). RESULTS: Mean diaphragmatic excursions in the BioGlue and glutaraldehyde groups were lower at 3 min and 30 min than in the albumin group (P < 0.05). Mean excursions in the gel group were similar to those of the albumin group (P = 0.9). Five BioGlue pigs (83%) and one gel pig (17%) had diaphragmatic paralysis by 30 min (P < 0.05 and P = 0.3 versus albumin, respectively). Coagulation necrosis extended into the myocardium at the cavoatrial junction in all 12 BioGlue pigs but only two gel pigs (33%, P < 0.01). Two BioGlue pigs (17%), but no gel pigs, had focal SAN degeneration and persistent bradycardia (P < 0.01). CONCLUSIONS: BioGlue causes acute nerve injury and myocardial necrosis that can lead to SAN damage. A water-soluble gel barrier is protective.

Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.

OBJECTIVE: Real-time information about regional spinal cord ischemia can guide intraoperative management and reduce the risk of paraplegia after thoracic aortic surgery. We hypothesized that near-infrared spectroscopy could provide such information during intercostal and lumbar artery ligation in pigs. METHODS: Transcutaneous near-infrared spectroscopic sensors were placed in the midline over the upper and lower thoracic vertebrae of 4 progressively larger pigs (weight range 21-70 kg). After the entire aorta was exposed, segmental arteries from T6 through L1 were sequentially ligated while regional oxygen saturation was monitored. Decreases in regional oxygen saturation were calculated as percentage changes from baseline. The degrees of ischemia in the upper and lower spinal cord were compared histopathologically. RESULTS: Baseline regional oxygen saturations were similar in the upper (68.8% +/- 9.0%) and lower (68.0% +/- 11.5%, P = .82) cord. After ligation, however, regional oxygen saturation levels were significantly lower in the lower cord (41.3% +/- 10.1%) than in the upper cord (64.8% +/- 9.3%, P = .037). The regional oxygen saturation had decreased by 39.0% +/- 11.5% in the lower cord but only by 6.3% +/- 7.6% in the upper cord (P = .026). This difference was confirmed microscopically: upper-cord sections had fewer ischemic neurons (8.8 +/- 9.4) than did lower-cord sections (21.3 +/- 13.6, P = .002). CONCLUSION: Intraoperative spinal cord ischemia was detectable with near-infrared spectroscopy in pigs weighing as much as 70 kg. The potential utility of this technique in patients undergoing thoracic aortic surgery warrants investigation.

Effect of age on peripheral vascular response to transverse aortic banding in mice.

The placement of a ligature to constrict the transverse aorta has become a standard procedure to induce cardiac hypertrophy in mice. Apart from cardiac response, there are adaptive changes in the proximal and distal arterial system that function to maintain adequate peripheral perfusion. The purpose of this study was to characterize the peripheral vascular response by measuring the carotid blood flow using noninvasive Doppler methods, and to investigate the effect of aging on the adequacy and timing of the response after aortic banding in mice. Five 16-month-old and 9 4-month-old male B6D2F1 mice underwent transverse aortic banding. Blood flow velocity was measured with Doppler in the right and left carotid arteries (RCA and LCA) before, 1 day after, and 7 days after, banding. Pulsatility index defined as (peak - minimum)/mean velocity was used to estimate local compliance and distal arterial resistance. The RCA/LCA mean velocity ratio was lower and pulsatility index ratio was higher at 1 day after banding in older mice. However, at 7 days, the RCA/LCA mean velocity ratio and pulsatility index ratio were similar between the 2 age groups. Our data indicate that there is an age-related delay in the development of vascular adaptations in carotid arteries after aortic banding. Older mice take a longer time for adaptation to establish adequate and equal mean flow velocity in the carotid arteries.

Measurement of aortic input impedance in mice: effects of age on aortic stiffness.

Mice are used with increasing frequency as models of human cardiovascular diseases, but significant gaps exist in our knowledge of vascular function in the aging mouse. We determined aortic input impedance spectra, pulse wave velocity, and augmentation index in adult (8-mo-old) and old (29-mo-old) mice to determine whether arterial stiffening occurred with age in mice as it does in humans. Pressure and blood velocity signals measured simultaneously from the same location in the ascending aorta were used to determine input impedance spectra (0-10 harmonics). The first minimum of the impedance modulus occurred at the second harmonic in adult mice but shifted to the fourth harmonic in old mice. Characteristic impedance (average of 2nd-10th harmonic) was 57% higher in old mice: 471 +/- 62 vs. 299 +/- 10 (SE) dyn.s.cm-3 (P < 0.05). Pulse pressure and augmentation index, determined from the aortic pressure signals, were also higher in old mice: 42 +/- 2.2 vs. 29 +/- 4.9 mmHg (P < 0.05) and 37 +/- 5 vs. 14 +/- 2% (P < 0.005). Aortic pulse wave velocity measured from the timing of upstrokes of the Doppler velocity signals was 45% higher in old mice: 416 +/- 22 vs. 286 +/- 14 cm/s (n = 3, P < 0.01). These results reproduce age-related findings reported in humans and confirm that mice may be used as models of age-related vascular stiffening.