Transcarotid arterial revascularization is feasible and safe with concomitant inferior vena cava occlusion

Transcarotid artery revascularization (TCAR) has risen as a promising minimally invasive intervention for high-risk patients with favorable anatomy. TCAR's noninferiority to carotid endarterectomy regarding stroke is reliant on its flow reversal technology and lack of aortic arch manipulation. We present the case of a 79-year-old man with a chronically occluded inferior vena cava who safely underwent staged bilateral TCAR for bilateral high-grade carotid artery stenosis. Although chronic inferior vena cava occlusion alters flow mechanics, we suspect that any pressure gradient facilitating retrograde flow from the carotid artery to the femoral vein provides neuroprotective benefits.

A review of arterial thoracic outlet syndrome

Arterial thoracic outlet syndrome (TOS) is a condition in which anatomic abnormalities in the thoracic outlet cause compression of the subclavian or, less commonly, axillary artery. Patients are usually younger and typically have an anatomic abnormality causing the compression. The condition usually goes undiagnosed until patients present with signs of acute or chronic hand or arm ischemia. Workup of this condition includes a thorough history and physical examination; chest x-ray to identify potential anatomic abnormalities; and arterial imaging, such as computed tomographic angiography or duplex to identify arterial abnormalities. Patients will usually require operative intervention, given their symptomatic presentation. Intervention should always include decompression of the thoracic outlet with at least a first-rib resection and any other structures causing external compression. If the artery is identified to have intimal damage, mural thrombus, or is aneurysmal, then arterial reconstruction is warranted. Stenting should be avoided due to external compression. In patients with symptoms of embolization, a combination of embolectomy, lytic catheter placement, and/or therapeutic anticoagulation should be done. Typically, patients have excellent outcomes, with resolution of symptoms and high patency of the bypass graft, although patients with distal embolization may require finger amputation.

Female Gender Increases Risk of Stroke and Readmission after CEA and CAS

OBJECTIVES

Carotid endarterectomy (CEA) has historically demonstrated a higher rate of perioperative adverse events for female patients. However, recent evidence suggests similar outcomes for CEA between genders. In contrast, fewer studies have examined gender in carotid artery stenting (CAS). Using contemporary data from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database, we aim to determine if gender impacts differences in postoperative complications in patients who undergo CEA or CAS.

METHODS

The ACS NSQIP database was queried from 2005-2017 using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes for retrospective review. Patients with carotid intervention (CEA or CAS) were stratified into asymptomatic vs symptomatic cohorts to determine the effect of gender on 30-day postoperative outcomes. Symptomatic patients were defined as those with perioperative transient cerebral ischemic attack or stenosis of carotid artery with cerebral infarction. Descriptive statistics were calculated. Risk-adjusted odds of 30-day postoperative outcomes were calculated using multivariate regression analysis with fixed effects for age, race, and comorbidities.

RESULTS

There were 106,568 patients with CEA or CAS (104,412 CEA and 2,156 CAS). Average age was 70.9 years old and female patients accounted for 39.9% of the population. For asymptomatic patients that underwent CEA or CAS, female gender was associated with significantly higher rates of CVA/stroke (13%, p=0.005), readmission (10%, p=0.004), bleeding complication (32%, p=0.001), and UTI (54%, p=0.001) as well as less infection (26%, p=0.001). In the symptomatic cohort, female gender was associated with significantly higher rates of CVA/stroke (32%, p=0.034), bleeding complication (203%, p=0.001), and UTI (70%, p=0.011), while female gender was associated with a lower rate of pneumonia (39%, p=0.039). Subset analysis found that, compared to male patients, female patients <75yo have an increased rate of CVA/stroke (21%, p=0.001) and readmission (15%, p<0.001), while female patients ≥75yo did not. In asymptomatic and symptomatic patients that underwent CEA, female gender was associated with significantly higher rates of CVA/stroke (13%, p=0.006 and 31%, p=0.044, respectively), but this finding was present not in patients undergoing CAS.

CONCLUSION

In patients undergoing carotid intervention, female gender was associated with significantly increased rates of postoperative CVA/stroke in the asymptomatic and symptomatic cohorts as well as readmission in the asymptomatic cohort. Female gender was associated with higher rates of CVA/stroke following CEA, but not CAS. We recommend that randomized control trials ensure adequate representation of female patients to better understand gender-based disparities in carotid intervention.

Contemporary Management of Acute Mesenteric Ischemia in the Endovascular Era

Objective:

Acute mesenteric ischemia is a rare disease entity associated with high morbidity and mortality. Disparate etiologies and nonspecific symptoms make the diagnosis challenging and often result in delayed diagnosis and intervention. Open laparotomy with mesenteric revascularization and resection of necrotic bowel has been considered the gold standard of care. With recent advances in percutaneous catheter-directed techniques, multiple retrospective studies have demonstrated the outcomes of endovascular therapy. Herein, we review the etiology, presentation, and diagnosis of acute mesenteric ischemia with contemporary outcomes associated with both open and endovascular treatments.

Methods:

The PubMed electronic database was queried in the English language using the search words mesenteric, acute ischemia, embolism, thromboembolism, thrombosis, revascularization, and endovascular in various combinations. Abstracts of the relevant titles were examined to confirm their relevance and the full articles then extracted. References from extracted articles were checked for any additional relevant articles. This systematic review encompassed literature for the past 5 years (between 2011 and 2016).

Results:

Early diagnosis and intervention improves acute mesenteric ischemia outcomes. Early restoration of mesenteric flow minimizes morbidity and mortality. In comparison to open laparotomy with mesenteric revascularization and resection of necrotic bowel, several retrospective studies using administrative data and single-center chart reviews demonstrate noninferior outcomes of an endovascular first approach in acute arterial mesenteric occlusion.

Conclusions:

For acute mesenteric arterial occlusive disease, both endovascular and open revascularization techniques are viable options. Although there is lack of level 1 evidence, single-center retrospective studies and administrative database studies demonstrated that an endovascular first approach may have improved outcomes in the immediate postoperative period. However, selection and other bias in these studies necessitate the need for definitive randomized prospective studies between endovascular and open mesenteric intervention. In contrast, mesenteric venous thrombosis may be treated with systemic anticoagulation without surgical revascularization. Catheter-directed thrombectomy and thrombolysis can be considered at the discretion of the clinician.

Malignancy Does not Affect Outcomes of Pharmacomechanical Thrombolysis in Acute Symptomatic Iliofemoral Deep Vein Thrombosis

BACKGROUND

Cancer patients demonstrate increased risk for venous thromboembolism (VTE), VTE recurrence, and anticoagulation-associated bleeding. Pharmacomechanical thrombolysis (PMT) aand thrombectomy improves venous patency, venous valve function, and quality of life in patients with acute iliofemoral deep vein thrombosis (DVT). It remains unknown whether pharmacomechanical thrombolysis can be used safely in patients with active cancer. We hypothesized that perioperative and short-term outcomes of pharmacomechanical iliofemoral DVT thrombolysis would not differ between patients with cancer and those without cancer.

METHODS

A retrospective chart review of consecutive patients with symptomatic iliofemoral DVT undergoing PMT by AngioJet Power Pulse spray and thrombectomy at a single tertiary care university institution between December 2013 and December 2016 was performed. Outcomes between patients with cancer and without cancer were compared.

RESULTS

We identified 22 limbs in 18 consecutive patients: 6 patients (7 limbs) with cancer and 12 patients (15 limbs) without cancer. Between these groups, the mean age was 60.5 ± 4.3 vs. 53.8 ± 26.8 years, respectively (P = 0.5593), and females comprised 66.7% vs. 25.0%, respectively (P = 0.0878). No significant difference in inferior vena cava (IVC) involvement between the groups (57.1% vs. 53.3%, P = 0.8676) was noted. Grade II (50-94% lysis) and III (95% complete lysis) thrombus lysis with restoration of venous patency was achieved in both the groups. Overnight catheter-directed thrombolysis (CDT) was rarely used. Notably, stenting was more frequently employed in cancer patients than in those without cancer (57.1% vs. 13.3%, P = 0.0316). The mean duration of follow-up was 3.42 ± 4.41 months for the cancer group and 4.50 ± 2.43 months for the noncancer group (P = 0.5060). Overall outcomes were excellent as no patient in both the groups experienced recurrent DVT, major bleeding, or postthrombotic syndrome. There was no mortality associated with the endovascular thrombolysis procedures.

CONCLUSIONS

The results of our study suggest that the presence of malignancy does not affect short-term outcomes of endovascular thrombolytic therapy in symptomatic DVT. Further follow-up is needed to evaluate long-term outcomes.

Carotid Body Tumor Resection: Just as Safe without Preoperative Embolization

BACKGROUND

Carotid body tumors (CBTs) are rare entities for which surgical resection remains the gold standard. Given their hypervascularity, preoperative embolization is often used; however, controversy exists over whether a benefit is associated. Proponents of embolization argue that it minimizes blood loss and complications. Critics argue that cost and stroke outweigh benefits. This study aimed to investigate the impact of embolization on outcomes following CBT resection.

METHODS

Patients undergoing CBT resection were identified using the Healthcare Cost and Utilization Project State Inpatient Database for 5 states between 2006 and 2013. Patients were divided into 2 groups: carotid body tumor resection alone (CBTR) and carotid body tumor resection with preoperative arterial embolization (CBETR). Descriptive statistics were calculated using arithmetic means with standard deviations for continuous variables and proportions for categorical variables. Patients were propensity score matched on the basis of sex, age, race, insurance, and comorbidity prior to analysis. Risk-adjusted odds of mortality, stroke, nerve injury, blood loss, and length of stay (LOS) were calculated using mixed-effects regression models with fixed effects for age, race, sex, and comorbidities.

RESULTS

A total of 547 patients were identified. Of these, 472 patients underwent CBTR and 75 underwent CBETR. Mean age was 54.7 ± 16 years. Mean number of days between embolization and resection was 0.65 ± 0.72 days (range 0-3). When compared with CBTR, there were no significant differences in mortality for CBETR (1.35% vs. 0%, P = 0.316), cranial nerve injury (2.7% vs. 0%, P = 0.48), and blood loss (2.7% vs. 6.8%, P = 0.245). Following risk adjustment, CBETR increased the odds of prolonged LOS (odds ratio 5.3, 95% confidence interval 2.1-13.3).

CONCLUSIONS

CBT resection is a relatively rare procedure. The utility of preoperative tumor embolization has been questioned. This study demonstrates no benefit of preoperative tumor embolization.

Mesenchymal Stem Cells Attenuate Hypoxic Pulmonary Vasoconstriction by a Paracrine Mechanism

BACKGROUND

Hypoxic pulmonary vasoconstriction (HPV) may be an adaptive mechanism to correct ventilation-perfusion mismatch in the face of hypoxia. In chronic hypoxia, prolonged vasoconstriction may result in pulmonary hypertension and cor pulmonale. It has been shown that during chronic hypoxia, mesenchymal stem cells (MSCs) may contribute to pulmonary vascular remodeling, anti-inflammation, and vascular stability. Also, MSCs have been shown to release growth factors when stressed by hypoxia. We hypothesized that MSCs reduce HPV by a paracrine mechanism. To test this, MSCs were stressed by hypoxia in tissue culture and the cell-free media was then used to treat the pulmonary arteries subjected to HPV.

METHODS

Adult male (250-350 g) Sprague Dawley rat pulmonary arteries (n = 10/group) were isolated and suspended in physiological organ baths. Human MSCs were stressed with 60-min hypoxia and conditioned media was collected. Pulmonary artery rings were treated with vehicle or MSC-conditioned (cell-free) media prior to hypoxia. Force displacement was continuously recorded. Data (mean +/- SEM) were analyzed with two-way analysis of variance with post-hoc Bonferroni test.

RESULTS

Pulmonary arteries exposed to MSC-conditioned media experienced an augmented vasodilatory phase as compared to vehicle. Maximum vasodilation was 53.58 +/- 6.42% versus 39.76 +/- 4.05% for vehicle (P < 0.001). In addition, delayed, phase II vasoconstriction was significantly attenuated as compared to vehicle. Maximum phase II vasoconstriction was 28.51 +/- 12.42 versus 86.29 +/- 15.99% for vehicle (P < 0.001).

CONCLUSIONS

We conclude that acute hypoxia induces HPV and that MSC-conditioned media acutely attenuates this effect. Thus, in addition to a direct contribution to vessel remodeling in chronic hypoxia, MSCs may acutely protect and attenuate hypoxic pulmonary vasoreactivity through a paracrine mechanism.

Sex differences in endothelial STAT3 mediate sex differences in myocardial inflammation

Recent studies have shown that females have improved myocardial functional recovery, TNF receptor 1 (TNFR1) signaling resistance, and increased STAT3 phosphorylation following acute ischemia/reperfusion (I/R) compared with males. We hypothesized that 1) STAT3 deficiency in endothelial cells (EC) impairs myocardial functional recovery in both sexes, 2) EC STAT3 deficiency equalizes sex differences in functional recovery, and 3) knockout of EC STAT3 decreases activation of myocardial STAT3 and increases p38 MAPK activation following acute I/R. Isolated male and female mouse hearts from WT and EC STAT3 knockout (STAT3KO) were subjected to 20-min ischemia/60-min reperfusion, and +/- dP/dt were continuously recorded. Heart tissue was analyzed for the active forms of STAT3 and p38 MAPK as well as expression of caspase-8 (Western blot) following I/R. EC STATKO had significantly decreased myocardial functional recovery in both sexes (%recovered +dP/dt: male 51.6 +/- 3.1 vs. 32.1 +/- 13.1%, female 79.1 +/- 3.6 vs. 43.6 +/- 9.1%; -dP/dt: male 52.2 +/- 3.3 vs. 28.9 +/- 12%, female 75.2 +/- 4.1 vs. 38.6 +/- 10%). In addition, EC STAT3KO neutralized sex differences in myocardial function, which existed in WT mice. Interestingly, EC STAT3 deficiency decreased myocardial STAT3 activation but increased myocardial p38 MAPK activation in both sexes; however, this was seen to a greater degree in females. We conclude that EC STAT3 deficiency resulted in decreased recovery of myocardial function in both sexes and neutralized sex differences in myocardial functional recovery following I/R. This observation was associated with decreased activation of myocardial STAT3 and increased activation of p38 MAPK in EC STAT3KO heart after I/R.

Endothelial STAT3 plays a critical role in generalized myocardial proinflammatory and proapoptotic signaling

Signal transducer and activator of transcription (STAT) 3 is involved in mediating a broad range of biological processes, including cell survival, proliferation, and immune response. Recent evidence has indicated that STAT3 in cardiomyocytes can be activated by ischemic-oxidative stress and exerts cardioprotection in the ischemic heart. There is no information, however, regarding the effect of endothelial cell-derived STAT3 on the myocardial response to ischemiareperfusion (I/R) injury. We hypothesized that the ablation of the STAT3 gene in endothelial cells would worsen postischemic myocardial function by affecting capillary network integrity, suppressing antiapoptotic signaling. Isolated hearts from wild-type and endothelial cell STAT3 knockout (STAT3KO) mice were subjected to 20 min of global ischemia followed by 60 min of reperfusion. Endothelial cell STAT3 deficiency decreased recovery of myocardial function in response to I/R, which was associated with higher levels of LDH release, decreased activation of myocardial STAT3, and elevated p38 MAPK activation in STAT3 endothelial knockout (KO) hearts. In addition, although no significant apoptosis was observed in wild-type and KO hearts, our results showed more expression of myocardial caspase-8 and more apoptosis in the myocardium around the capillary in STAT3KO mice subjected to I/R. Furthermore, endothelial cell STAT3 ablation resulted in increased myocardial expression of IL-6 and suppressor of cytokine signal 3. This study demonstrates that endothelial cell-derived STAT3 plays an important role in postischemic myocardial function.

STAT3 mediates bone marrow mesenchymal stem cell VEGF production

The mechanisms by which mesenchymal stem cells (MSCs) may protect native tissue are incompletely understood. Understanding the mechanisms by which these cells release factors such as vascular endothelial growth factor (VEGF), may lead to enhanced protection. We hypothesized that stress, in the form of hypoxia or TNF, activates MSCs to release VEGF by STAT3 and p38 MAPK dependent mechanisms. Mouse MSCs from wild type (WT) and STAT3 knockout mice (STAT3KO) were harvested and purified by a single-step method using adhesion. The release of VEGF was analyzed by using MSC conditioned media under hypoxia or TNF stimulation with or without p38 MAPK inhibition. Activation of STAT3 and p38 MAPK was determined by analysis of cell lysates. MSCs released VEGF under normoxia, which was associated with constitutive STAT3 activity. STAT3 deficiency resulted in decreased MSC production of VEGF. In response to hypoxia or TNF, MSCs produced more VEGF, which was correlated with hypoxia or TNF activated p38 MAPK and STAT3. The p38 MAPK inhibitor significantly decreased hypoxia-induced or TNF-stimulated VEGF production in WT. Additionally, STAT3 ablation neutralized hypoxia-induced MSC release of VEGF. No effect of p38 MAPK inhibitor alone was observed on MSC release of VEGF in WT. However, inhibition of p38 MAPK blocked release of VEGF in STAT3KO MSCs. MSCs are a potent source of VEGF, the production of which is mediated by STAT3 under normoxia partly; however, following hypoxia or TNF exposure, MSC release of VEGF is mediated by both STAT3 and p38 MAPK.

Deficiency of TNFR1 protects myocardium through SOCS3 and IL-6 but not p38 MAPK or IL-1beta

Tumor necrosis factor-alpha (TNF-alpha) plays an important role in the development of heart failure. There is a direct correlation between myocardial function and myocardial TNF levels in humans. TNF may induce local inflammation to exert tissue injury. On the other hand, suppressors of cytokine signaling (SOCS) proteins have been shown to inhibit proinflammatory signaling. However, it is unknown whether TNF mediates myocardial inflammation via STAT3/SOCS3 signaling in the heart and, if so, whether this effect is through the type 1 55-kDa TNF receptor (TNFR1). We hypothesized that TNFR1 deficiency protects myocardial function and decreases myocardial IL-6 production via the STAT3/SOCS3 pathway in response to TNF. Isolated male mouse hearts (n = 4/group) from wild-type (WT) and TNFR1 knockout (TNFR1KO) were subjected to direct TNF infusion (500 pg.ml(-1).min(-1) x 30 min) while left ventricular developed pressure and maximal positive and negative values of the first derivative of pressure were continuously recorded. Heart tissue was analyzed for active forms of STAT3, p38, SOCS3 and SOCS1 (Western blot analysis), as well as IL-1beta and IL-6 (ELISA). Coronary effluent was analyzed for lactate dehydrogenase (LDH) activity. As a result, TNFR1KO had significantly better myocardial function, less myocardial LDH release, and greater expression of SOCS3 (percentage of SOCS3/GAPDH: 45 +/- 4.5% vs. WT 22 +/- 6.5%) after TNF infusion. TNFR1 deficiency decreased STAT3 activation (percentage of phospho-STAT3/STAT3: 29 +/- 6.4% vs. WT 45 +/- 8.8%). IL-6 was decreased in TNFR1KO (150.2 +/- 3.65 pg/mg protein) versus WT (211.4 +/- 26.08) mice. TNFR1 deficiency did not change expression of p38 and IL-1beta following TNF infusion. These results suggest that deficiency of TNFR1 protects myocardium through SOCS3 and IL-6 but not p38 MAPK or IL-1beta.

Estrogen receptor-alpha mediates acute myocardial protection in females

Sex differences in myocardial recovery have been reported after acute ischemia and reperfusion injury. Estrogen and the estrogen receptor are critical determinants of cardiovascular sex differences. However, the mechanistic pathways responsible for these differences remain unknown. We hypothesized that estrogen receptor-alpha is an important modulator of 1) myocardial functional recovery after ischemia and 2) inflammatory signaling via MAPK. To study this, adult male and female wild-type (WT) and estrogen receptor-alpha knockout (ER1KO) mouse hearts were isolated, perfused via Langendorff model, and subjected to 20 min of ischemia and 60 min of reperfusion. Myocardial contractile function (left ventricular developed pressure and positive and negative first derivative of pressure) was continuously recorded. After ischemia-reperfusion, hearts were assessed for expression of inflammatory cytokines (ELISA) and activation of MAPK and caspase-3 (Western blot analysis). Data were analyzed with two-way ANOVA or Student's t-test, and P < 0.05 was statistically significant. ER1KO females exhibited significantly less functional recovery than WT females and were similar to WT males. Activated ERK was increased in female WT hearts compared with female ER1KO. Activated JNK was decreased in female WT hearts compared with female ER1KO. No significant differences were found between male WT, female WT, male ER1KO, and female ER1KO in activated p38 MAPK, proinflammatory cytokine expression, and proapoptotic signaling. Estrogen receptor-alpha plays a role in the protection observed in the female heart. Differential activation of MAPK may mediate this protection. Further studies are necessary to delineate these mechanistic pathways.

ZAPRINAST ATTENUATES HYPOXIC PULMONARY ARTERY INJURY AND CAUSES LESS AORTIC RELAXATION THAN MILRINONE

Hypoxic pulmonary vasoconstriction is a challenging clinical problem with limited therapeutic options. Milrinone, a phosphodiesterase (PDE)-3 inhibitor, is frequently used to treat perioperative pulmonary hypertension. However, recent evidence suggests that the PDE-5 isoform may be more specific for lung tissue. We hypothesized that the PDE-5 inhibitor zaprinast has greater efficacy for pulmonary vasorelaxation, attenuation of hypoxic pulmonary vasoconstriction, and inhibition of hypoxia-induced pulmonary artery cytokine expression when compared with milrinone. To study this, isolated rat pulmonary artery and thoracic aorta rings suspended in physiologic organ baths for measurement of isometric force transduction were treated with vehicle (dimethyl sulfoxide), milrinone, or zaprinast to assess pulmonary artery relaxation, thoracic aorta relaxation, inhibition of hypoxic (pO2 = 30-35 mmHg) pulmonary vasoconstriction, and hypoxia-induced pulmonary artery TNF-alpha and IL-1beta expression (reverse transcriptase-PCR). Milrinone and zaprinast resulted in dose-dependent pulmonary artery and aortic relaxation, but zaprinast caused significantly less aortic relaxation compared with milrinone (50.12% +/- 3.36% versus 91.03% +/- 2.97%, P < 0.001). Zaprinast, but not milrinone, significantly inhibited hypoxic pulmonary vasoconstriction (zaprinast, 58.42% +/- 5.37%; milrinone, 77.65% +/- 4.42% versus vehicle: 74.42% +/- 7.54%). Hypoxia-induced upregulation of TNF-alpha and IL-1beta mRNA in pulmonary artery was decreased by zaprinast, but not milrinone, pretreatment. These results suggest that zaprinast, but not milrinone, preferentially vasodilates pulmonary artery over aorta, attenuates hypoxic pulmonary vasoconstriction, and inhibits hypoxia-induced pulmonary artery TNF-alpha and IL-1beta expression. Therefore, PDE-5 inhibition may be advantageous in the treatment of pulmonary hypertension.

Does endogenous testosterone mediate the lower preconditioning threshold in males?

BACKGROUND

Preconditioning is injury-induced protection from subsequent insult. Recent data indicates that males have lower preconditioning thresholds compared to females. Therefore, we hypothesized that testosterone may mediate the lower preconditioning threshold observed in males.

MATERIALS AND METHODS

Adult normal and castrated male Sprague-Dawley rats (n = 4-5) were given intraperitoneal (i.p.) injections of 125 or 500 microg/kg Salmonella typhimurium lipopolysaccharide (ETX) or 0.4 ml normal saline (NS). Another i.p. injection of 500 microg/kg ETX (injury dose) was given 24 h later. After 6 h, myocardial function was evaluated via the Langendorff perfusion model. Shams received only NS, while non-preconditioned rats (PC-) received NS followed by the 500 microg/kg ETX injury dose. Preconditioned rats received injections of 125 mug/kg ETX (PC +125) or 500 microg/kg ETX (PC +500), followed by the 500 microg/kg ETX injury dose.

RESULTS

Normal PC +125 and PC +500 males were preconditioned and maintained cardiac function similar to shams (P > 0.05). Castrated PC +125 and PC +500 males were also preconditioned and maintained cardiac function similar to castrated shams (P > 0.05). Conversely, both normal and castrated PC-males showed significantly decreased cardiac function compared to shams (P < 0.05).

CONCLUSIONS

Endogenous testosterone does not mediate the lower preconditioning threshold in males.