Left ventricular free wall rupture caused by myocardial ischemia without treatable atherosclerotic coronary disease: a case series

BACKGROUND

The clinical presentation of left ventricular free wall rupture (LVFWR) varies ranging from uneventful condition to congestive heart failure. Here we report two cases of LVFWR with different clinical presentation and notable outcome. A 53-year-old male presenting emergently with signs of myocardial infarction received immediate coronary angiography and thoracic CT-scan showing occlusion of the first marginal coronary branch without possibility of revascularization and minimal pericardial extravasation. Under ICU surveillance, LVFWR occurred 24 h later and was treated by pericardiocentesis and ECMO support followed by immediate uncomplicated surgical repair. Postoperative therapy-refractory vasoplegia and electromechanical dissociation caused fulminant deterioration and the early death of the patient. The second case is a 76-year old male brought to the emergency room after sudden syncope, clinical sings of pericardial tamponade and suspicion of a type A acute aortic dissection. Immediate CT-angiography excluded aortic dissection and revealed massive pericardial effusion and a hypoperfused myocardial area on the territory of the first marginal branch. Immediate sternotomy under mechanical resuscitation enabled removal of the massive intrapericardial clot and revealed LVFWR. After an uncomplicated surgical repair, an uneventful postoperative course, the patient was discharged with sinus rhythm and good biventricular function. One year after the operation, he is living at home, symptom free.

DISCUSSION

Whereas the younger patient, who was clinically stable at hospital admission received delayed surgery and did not survive treatment, the older patient, clinically unstable at presentation, went into immediate surgery and had a flawless postoperative course. Thus, early surgical repair of LVFWR leads to best outcome and treating LVFWR as a high emergency regardless of the symptoms improve survival.

Sequential composite BIMA grafting for 3v-CAD: factors that predict successful outcome of the one-inflow and two-inflow revascularization techniques

OBJECTIVE

The effect of one-inflow and two-inflow coronary surgical revascularization techniques inclosing skeletonized double mammary artery (BIMA) as T-graft on outcome is studied.

METHODS

Early ad mid-term outcome of complete BIMA revascularization (C-T-BIMA) versus left-sided BIMA with right-sided aorto-coronary bypass (L-T-BIMA + R-CABG) is quantified and analyzed by multivariate logistic regression, Cox-regression, and Kaplan-Meier analysis in a series of 204 consecutive patients treated for triple-vessel coronary disease (3v-CAD).

RESULTS

The L-T-BIMA + R-CABG technique (n = 104) enables higher number of total (4.02 ± 0.87 vs. 3.71 ± 0.69, p = 0.015) and right-sided (1.21 ± 0.43 vs. 1.02 ± 0.32, p = 0.001) coronary anastomoses, improves total bypass flow (125.88 ± 92.41 vs. 82.50 ± 49.26 ml, p < 0.0001) and bypass flow/anastomosis (31.83 ± 23.9 vs.22.77 ± 14.23, p = 0.001), and enhances completeness of revascularization (84% vs.69%, p = 0.014) compared to C-T-BIMA strategy (n = 100), respectively. Although the incidence of MACCE was comparable in the two groups (8% vs.1.2%, p = 0.055), the progression of functional mitral regurgitation (FMR) was significantly lower after L-T-BIMA + R-CABG, then after C-T-BIMA (47% vs.64%, p = 0.017). The use of C-T-BIMA-technique (HR = 4.2, p = 0.01) and preoperative RCA occlusion (HR = 3.006, p = 0.023) predicted FMR progression, whereas L-T-Graft + R-CABG technique protected against it (X2 = 14.04, p < 0.0001) independent of the anatomic and clinical complexity (Syntax score I: HR = 16.2, p = 0.156, Syntax score II: HR = 1.901, p = 0.751), of early- (0.96% vs.2%, p = 0.617) and mid-term mortality (5.8% vs.4%, p = 0.748) when compared to C-T-BIMA, respectively.

CONCLUSIONS

The two-inflow coronary revascularization by L-T-BIMA + R-CABG better protects against FMR progression without increasing MACCE and mortality. Older patients with RCA occlusion and reduced LV-EF benefit most from the two-inflow L-T-BIMA + R-CABG technique. Younger 3v-CAD patients with normal LV-EF can preferentially be managed with the one-inflow C-T-BIMA; however, long-term outcome remains to be revealed.

Outcome of Surgery for Ischemic Mitral Regurgitation Depends on the Type and Timing of the Coronary Revascularization

OBJECTIVE

Long-term outcomes of mitral valve (MV) repair versus MV replacement for ischemic mitral regurgitation (IMR) in patients undergoing either prior (PCR) or concomitant coronary revascularization (CCR) by surgery (CABG) or intervention (PCI) are uncertain.

METHODS AND RESULTS

Of 446 patients receiving MV surgery for IMR between July 2006 and December 2010, 125 patients-87 CCR (69.1%) and 38 PCR (30.9%)-were eligible for inclusion in the study. Survival was higher in CCR versus PCR at long-term follow-up (78.83% vs. 57.9%, p = 0.016). The incidence of MACCE was lower in the CCR compared to PCR at both hospital discharge (34.11% vs. 63.57%, p = 0.003) and at follow-up (34.11% vs. 65.79%, p = 0.0008). Patients receiving CABG or CABG with PCI in PCR had higher mortality risks after MV surgery than CCR patients (X² = 6.029, p = 0.014 and X² = 6.466, p = 0.011, respectively). Whereas in the PCR group, MV repair and MV replacement achieved similar survival probability (X² = 1.551, p = 0.213), MV repair in the CCR group led to improved survival compared to MV replacement (X² = 3.921, p = 0.048). In MV replacement, LAD-CABG improved survival compared to LAD-PCI (U = 15,000.00, Z = -2.373 p = 0.018), and a substantial impact of arterial IMA-LAD grafting was revealed in the Cox-regression analysis (HR 0.334, CI: 0.113-0.989, p = 0.048) as opposed to venous-LAD grafting (HR 0.588, CI: 0.166-2.078, p = 0.410).

CONCLUSION

Early treatment of IMR concomitant to coronary revascularization enhances long-term survival compared to delayed MV surgery after PCR. MV repair is not superior to MV replacement when performed late after coronary revascularization; however, MV repair leads to better survival than MV replacement when performed concomitantly with CABG with arterial LAD revascularization.

Impact of the underlying aortic pathology on postimplantation syndrome after endovascular thoracic aortic repair

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) is the treatment option of choice for almost all pathologies of the descending thoracic aorta. The aim of the present study was to determine the impact of aortic pathology on the occurrence of postimplantation syndrome (PIS) after TEVAR.

METHODS

Seventy-four patients undergoing TEVAR for aortic dissection (TAD, 25), aortic aneurysm (TAA, 26), and aortic rupture or perforated ulcer (TAR/PAU, 23) were included in this retrospective study. The clinical outcome measures were persistent inflammation at hospital discharge and in-hospital mortality.

RESULTS

PIS was assessed in 22.97% of all patients, predominantly in the TAD group (P=0.03). CRP increased after TEVAR (156.6±94.5, P<0.001; 108.1±57.7, P<0.01 and 117.8±70.4, P<0.05) vs. baseline (58.1±77.5, 31.94±52.1 and 31.9±52.1 mg/L, in TAD, TAA and TAR/PAU, respectively) and this increase was more accentuated in TAD group (P<0.05). Stent-length was similar in all groups (P=0.226) but correlated with postoperative CRP only in TAD (R=0.576, P=0.013). Fresh parietal thrombus correlated with CRP (R=0.4507, P=0.0005) and is (OR=1.0883, P=0.0001), together with the pathology of aortic dissection (OR=6.2268, P=0.0288), a predictor of PIS after TEVAR. Whereas mortality (5.4%) did not correlate with PIS (P=0.38) either with aortic pathology (P=0.225), hospital stay after TEVAR was significantly prolonged by PIS (P=0.03).

CONCLUSIONS

Aortic dissection is associated with more inflammation after TEVAR than aortic aneurysm, rupture or perforated ulcer, with the amount of fresh parietal thrombus playing the most significant role in the occurrence of PIS. Importantly, PIS prolongs hospital stay but not mortality after TEVAR.

Differentiated impact of pulmonary hypertension on outcome after left ventricular assist device implantation and tricuspid valve repair

The present study aimed to investigate the impact of pulmonary hypertension (PH) on short-term survival after LVAD implantation with or without tricuspid annuloplasty valve repair (TVr) performed to treat regurgitation and avoid RV-failure post-LVAD insertion. Data of 24 patients receiving LVAD-implantation are assessed and compared. The primary outcome is in-hospital survival. Of 24 patients studied, 17 (70.8%) survived hospital stay: age (62.2 ± 12.3 vs 66.1 ± 8.5 years), preoperative LV-EF (15.9 ± 5.3% vs 13.6 ± 3.8%) vs. non-survivors, respectively. Survivors received preoperatively Impella (35.3% vs 0%, p = 0.037), had shorter intubation time (3.3 ± 3.5 vs 11.4 ± 11.1 days, p = 0.0053) and ICU stay (12.4 ± 9.8 vs 34.3 ± 34 days, p = 0.01) versus non-survivors. Non-survivors had more severe PH (37.0 ± 9.6 vs 29.8 ± 12.2 mmHg, p = 0.044) than survivors. Linear regression analysis revealed that cardiac operations performed concomitant with LVAD implantation increased mortality in patients with severe PH (p = 0.04), whereas isolated TVr performed concomitant with LVAD implantation did not increase mortality neither in the entire patient cohort (p = 0.569) nor in patients with severe PH (p = 0.433). LVAD with TVr improved survival in patients suffering from severe PH (vs. moderate PH), however this difference did not reach the level of significance due to the small number of patients (p = 0.08). LVAD-implantation alone improved survival of patients suffering from moderate PH (p = 0.045, vs. severe PH). Surgical correction of tricuspid regurgitation concomitant or before LVAD implantation improves early survival in patients suffering from severe PH when compared to LVAD implantation alone. Patients suffering from severe PH tend to benefit more from TVr than those suffering from moderate PH.

Risk factors for postoperative delirium after cardiac surgical procedures with cardioplegic arrest

OBJECTIVES

The pathophysiology of delirium after cardiac surgery is complex. The present study aims to determine perioperative risk factors and construct a scoring system for postoperative delirium based on the type of surgery.

METHODS

Three hundred patients undergoing coronary artery bypass grafting (CABG; n = 150) or valve and/or aortic surgery ± CABG (n = 150) were retrospectively evaluated.

RESULTS

The incidence of delirium (32%) was similar in subgroups (28.7% and 33.33%, P = 0.384). Delirium patients were older [71.3 (standard deviation: 8.5) vs 66.6 (standard deviation: 9.5), P < 0.001; 70.0 (standard deviation: 9.6) vs 62.5 (standard deviation: 12.6), P < 0.001] and required more packed red blood cell units [2.1 (standard deviation: 2.1) vs 4.2 (standard deviation: 4.0), P < 0.001; 2.4 (standard deviation: 3.3) vs 5.4 (standard deviation: 5.9), P < 0.001] and fresh frozen plasma units [6.1 (standard deviation: 2.9) vs. 8.0 (standard deviation: 4.2), P < 0.001; 6.3 (standard deviation: 3.4) vs 10.8 (standard deviation: 7.2), P < 0.001] in CABG and valve/aortic subgroups, respectively. Delirium was associated with longer operation time [298.3 (standard deviation: 98.4) vs 250.6 (standard deviation: 67.8) min, P < 0.001], cardiopulmonary bypass (CPB) time [171.5 (standard deviation: 54.9) vs 140.98 (standard deviation: 45.8) min, P < 0.001] and cardiac arrest time [112 (standard deviation: 35.9) vs 91.9 (standard deviation: 28.6), P < 0.001] only in the valve/aortic group (versus non-delirium). Multivariate regression analysis identified an association between delirium and age [odds ratio: 1.056 (95% confidence interval: 1.002-1.113), P = 0.041], CPB time [odds ratio: 1.1014 (95% confidence interval: 1.004-1.025), P = 0.007], fresh frozen plasma transfusion [odds ratio: 1.127 (95% confidence interval: 1.006-1.262), P = 0.039] and atrial fibrillation [odds ratio: 4.801 (95% confidence interval: 1.844-12.502), P < 0.001] after valve/aortic surgery (area under the curve 0.835, P < 0.001) and between delirium and age [odds ratio: 1.089 (95% confidence interval: 1.023-1.160), P = 0.007] and ventilation time [odds ratio: 1.068 (95% confidence interval: 1.026-1.113), P = 0.001] after isolated CABG (area under the curve 0.798, P < 0.001). The cross-validation of the results by k-fold logistic regression revealed for the entire patient cohort an overall average accuracy of the prediction model of 0.764, with a false-positive rate of 0.052 and a false-negative rate of 0.18.

CONCLUSIONS

Age, CPB time, ventilation, transfusion and atrial fibrillation are differently associated with delirium depending on the operative characteristics. Optimization of intraoperative parameters and use of risk calculators may enable early institution of pharmacotherapy and improve overall outcome after cardiac surgery.

Video-assisted minimal access surgery for complicated mitral valve endocarditis, tricuspid valve insufficiency and progressive coronary disease after previous CABG - in the time of COVID-19: a case report

BACKGROUND

The timing for heart surgery following cerebral embolization after cardiac valve vegetation is vital to postoperative recovery being uneventful, additionally Covid-19 may negatively affect the outcome. Minimally invasive methods and upgraded surgical instruments maximize the benefits of surgery also in complex cardiac revision cases with substantial perioperative risk.

CASE PRESENTATION

A 68 y.o. patient, 10 years after previous sternotomy for OPCAB was referred to cardiac surgery on the 10th postoperative day after neurosurgical intervention for intracerebral bleeding with suspected mitral valve endocarditis. Mitral valve vegetation, tricuspid valve insufficiency and coronary stenosis were diagnosed and treated by minimally invasive revision cardiac surgery on the 14th postoperative day after neurosurgery.

CONCLUSION

The present clinical case demonstrates for the first time that the minimally invasive approach via right anterior mini-thoracotomy can be safely used for concomitant complex mitral valve reconstruction, tricuspid valve repair and aorto-coronary bypass surgery, even as a revision procedure in the presence of florid endocarditis after recent neurosurgical intervention. The Covid-19 pandemic and prophylactic patient isolation slow down the efficacy of pulmonary weaning and mobilisation and prolong the need for ICU treatment, without adversely affecting long-term outcome.

A minimally invasive approach for open surgical thoracoabdominal aortic replacement: experimental concept for a novel surgical procedure

Objectives

We aimed to develop a simple, reliable, and timesaving technique for the therapy of thoracoabdominal aortic (TAA) aneurysms that are not suitable for endovascular repair.

Methods

In this pilot study, we sought to combine the advantages of classic open vascular procedure with the use of endoscopic surgical tools and small skin incisions to develop a minimally invasive approach for TAA replacement. The following procedures were used: endoscopic exposure and closure of the lower intercostal arteries; small posterolateral thoracotomy and left retroperitoneal incisions to expose the anastomotic regions of the aorta; partial anticoagulation; passive bypass and sequential aortic clamping; tunnelling of the graft through the native aortic lumen (endoaneurysmorrhaphy) and open performance of vascular anastomosis.

Results

Five mixed-breed dogs (25-35 kg) underwent minimally invasive TAA replacement. All animals survived the operation without blood transfusion (lowest Hb = 5.5 mg/dl). Total operation time was 364 ± 46.3 min. Clamping times were 17.6 ± 3.2 min for proximal anastomosis, 33.2 ± 2.48 min for visceral patch and 11 ± 2.3 min for distal anastomosis. The pull-through procedure of graft through the native aorta was performed during the visceral clamp time.

Conclusions

Surgical replacement of the TAA through small transverse incisions of the thoracic and abdominal wall is feasible and allows open performance of all vascular anastomosis with no leakage at any anastomotic site. Further experimental studies and clinical implementation are needed to establish the safety and long-term outcome of minimally invasive TAA replacement as a possible primary therapeutic tool for complex aneurysms that are not suitable for endovascular treatment and require open surgical repair.

Elliptical transection for eversion endarterectomy enables efficient external carotid artery desobliteration

BACKGROUND

Eversion endarterectomy (EEA) of the internal carotid artery requires less distal surgical exposure than conventional patch reconstruction endarterectomy. However, the technical success after EEA was tremendously contradictive especially with respect to the external carotid artery (ECA) patency rate. The purpose of this study was to determine the effect of elliptical EEA on the quality and outcome of external carotid artery desobliteration.

METHODS

Clinical outcome and carotid disease progression at one year were evaluated in thirty patients receiving EEA through short transverse skin incision either in general anesthesia (GA, 22 patients) or locoregional anesthesia (LRA, 8 patients).

RESULTS

One patient (GA group) required early revision for bleeding. There was no postoperative stroke, nerve damage or death. At one year, ipsilateral systolic peak velocity (SPV) measurements showed no disease progression in the internal (75.30±19.31; 62.88±28.51 cm/s) or in the external carotid artery (118.92±58.30; 79.00±27.15 cm/s, GA; RLA, respectively). The incidence of ipsilateral ECA stenosis >50% decreased from 64% preoperatively to 16 % at one year (P<0.001). On the contralateral side, incidence of ECA stenosis >50% increased from 27% preoperatively to 56% after one year (p=0.018). On the ipsilateral side, all patients in the RLA group had less than 50% stenosis of ECA at one year after the operation (P=0.021 vs. pre-OP), while in the GA group four patients developed 50-74% stenosis and one patient >75% stenosis of ECA (P<0.001 vs. pre-OP). These results were not significantly different between the two groups and demonstrated a total of 96.7% ECA patency at one year.

CONCLUSIONS

Elliptical transsection for EEA enables outstanding ECA revascularization with good patency at one year. Type of anesthesia does not affect the quality of the eversion technique.

Effect of haemodynamic changes on epithelium-related intestinal injury in off-pump coronary surgery

OBJECTIVES

Intestinal injury is thought to play a central role in the occurrence of multiorgan dysfunction after on-pump coronary surgery. Clinical benefits of off-pump revascularisation remain, however, controversial.

MATERIAL AND METHODS

Hepatic enzymes and plasmatic IL-6, IL-8 and intestinal-type fatty acid binding protein (I-FABP) were determined in 20 patients (age 65-75) undergoing either on-pump (n = 10) or off-pump (n = 10) coronary surgery. Haemodynamic and biochemical parameters, catecholamine and volume therapy were monitored.

RESULTS

Central venous pressure (CVP) was significantly higher in the off-pump group during and 12h after operation (9.5 ± 1.35 vs. 6.21 ± 0.63 mmH2O, p = 0.012). Higher GGT and GLDH levels occurred in the off-pump group and correlated with the elevated I-FABP levels at 24h (935.8 ± 83.7 vs. 370.4 ± 67.7 pg/mL, p<0.001). CVP correlated with I-FABP peak values (Pearson's coefficient 0.852). IL-6 and IL-8 were released to a lower extent in the off-pump group compared to on pump (p<0.05) at 24h (139.3 ± 27.7 vs. 279.4 ± 56.2 and 15.3 ± 7.4 vs. 38.5 ± 13.8 pg/mL) and at 72 h post-operatively (4.5 ± 2.1 vs. 30.1 ± 12.1 and 7.8 ± 1.2 vs. 17.1 ± 5.2 pg/mL).

CONCLUSIONS

While inflammatory activation is reduced with CPB avoidance, elevated CVP during off-pump surgery is followed by temporary postoperative enterocyte damage that may threaten the normal function of the gastrointestinal system and lead - in certain groups of high risk patients--to irrecoverable injury.

MESENTERIC VASCULAR DYSFUNCTION AFTER CARDIOPULMONARY BYPASS WITH CARDIAC ARREST IS AGGRAVATED BY COEXISTENT HEART FAILURE

Although patients suffering from heart failure (HF) have an increased incidence of nonocclusive mesenteric ischemia after opened heart surgery, the impact of cardiopulmonary bypass with cardiac arrest (CPB) on mesenteric vascular circulation in such situation remains unexplored. Therefore, the present study investigates the effects of CPB on mesenteric vascular reactivity, regional metabolism, and oxidative stress in an experimental model of HF. Volume-overload HF was induced in six dogs by bilateral femoral arteriovenous fistula. Six sham-operated dogs were used as controls. Eight weeks later, the short-term effects of 90 min of CPB were assessed in vivo during acute experiments. The significant increase in left ventricular end-diastolic volume in HF animals did not influence the vasodilator response of the superior mesenteric artery to acetylcholine (ACH) and nitroprusside (SNP) under baseline conditions. However, reduced mesenteric oxygen delivery, increased oxygen extraction, and lactate release were found during CPB in the HF group. In addition, an increased free radical production was assessed in the HF group during (89 +/- 23 x 10 relative light units [RLU]) and after CPB (93 +/- 15 x 10 RLU) compared with controls (45 +/- 15 and 49 +/- 7 x 10 RLU, respectively). Finally, 90 min of CPB led to a more pronounced decrease of ACH- (-22% +/- 5% vs. -42% +/- 9%, P < 0.05) and SNP- (-14% +/- 4% vs. -50% +/- 7%, P < 0.002) induced mesenteric vasodilations in the HF group compared with controls. We conclude that coexistent HF significantly enhances the pathological effects of CPB on the mesenteric vascular circulation by additionally altering endothelial and smooth muscle vascular function consequent to augmented oxidative stress.

Poly(ADP-ribose) polymerase inhibitor PJ-34 reduces mesenteric vascular injury induced by experimental cardiopulmonary bypass with cardiac arrest

The aim of this study was to investigate effects of poly(ADP-ribose) polymerase (PARP) inhibition on mesenteric vascular function and metabolism in an experimental model of cardiopulmonary bypass (CPB) with cardiac arrest. Twelve anesthetized dogs underwent 90-min hypothermic CPB. After 60 min of cardiac arrest, reperfusion was started for 40 min following application of either saline vehicle (control, n = 6) or a potent PARP inhibitor, PJ-34 (10 mg/kg iv bolus and 0.5 mg.kg(-1).min(-1) infusion for 20 min, n = 6). PJ-34 led to better recovery of cardiac output (2.2 +/- 0.1 vs. 1.8 +/- 0.2 l/min in control) and mesenteric blood flow (175 +/- 38 vs. 83 +/- 4 ml/min, P < 0.05 vs. control) after reperfusion. The impaired vasodilator response of the superior mesenteric artery to acetylcholine, assessed in the control group after CPB (-32.8 +/- 3.3 vs. -57.6 +/- 6.6% at baseline, P < 0.05), was improved by PJ-34 (-50.3 +/- 3.6 vs. -54.3 +/- 4.1% at baseline, P < 0.05 vs. control). Although plasma nitrate/nitrite concentrations were not significantly different between groups, mesenteric nitric oxide synthase activity was increased in the PJ-34 group (P < 0.05). Moreover, the treated group showed a marked attenuation of mesenteric venous plasma myeloperoxidase levels after CPB compared with the control group (75 +/- 1 vs. 135 +/- 9 ng/ml, P < 0.05). Pharmacological PARP inhibition protects against development of post-CPB mesenteric vascular dysfunction by improving hemodynamics, restoring nitric oxide production, and reducing neutrophil adhesion.

ET(A) receptor blockade protects the small intestine against ischaemia/reperfusion injury in dogs via an enhancement of antioxidant defences

The aim of the present study was to determine whether the ET(A) receptor antagonist LU135252 can protect the mesenterium against ischaemia/reperfusion (I/R) damage. Direct occlusion of the superior mesenteric artery was performed for 30 min in two groups of dogs. Declamping was followed by 90 min of reperfusion. Mesenteric release of ET-1 was studied in series 1 (n=6). In series 2, 5 min before cross-clamping, the treated group (n=7) received an intravenous bolus of LU135252 (5 mg/kg), whereas the control group (n=6) was given vehicle. Mean arterial blood pressure and mesenteric blood flow were recorded. Mesenteric venous and systemic arterial serum lactate and glucose, plasma creatine kinase and free radical concentrations were determined at 15 min intervals. Ischaemia for 30 min induced a significant increase (P<0.05) in mesenteric ET-1 release (1594+/-526 pg/min, compared with 343+/-258 pg/min at baseline), which had returned to baseline after 20 min of reperfusion. LU135252 administration significantly decreased mesenteric blood flow during ischaemia (204+/-23%) compared with controls (320+/-34%, P<0.05). In contrast, mesenteric blood flow was higher in the treated group (120+/-19% compared with 82+/-7%; P<0.05) after 90 min of reperfusion. Mesenteric lactate production was reduced by ET(A) antagonist administration under ischaemia (0.77+/-0.02 mmol/l) compared with controls (1.36+/-0.04 mmol/l; P<0.01). Lower levels of venous creatine kinase were present in the treated group during ischaemia as well as after reperfusion (120+/-7% compared with 150+/-16%; P<0.01). Administration of LU135252 also improved the total scavenger capacity of the mesenteric bed during ischaemia [(15.9+/-3.9)x10(6) compared with (6.4+/-3.6)x10(6) relative light units; P<0.05] and early reperfusion [(8.7+/-3.1)x10(6) compared with (1.1+/-2.9)x10(6) relative light units]. Thus ET-1 is involved in I/R-induced disturbances in the intestine. LU135252 seems to counteract these changes, in part by increasing the antioxidant capacity of the mesenterium.