Patterns of left ventricular longitudinal myocardial dysfunction in mitral valve prolapse and effects of valve repair

Background

Regional longitudinal left ventricular (LV) dysfunction in patients with mitral regurgitation (MR) due to valve prolapse (MVP) with normal ejection fraction has been recently described, with data pointing at dysfunction of the LV base related to dilatation of the mitral annulus.

Purpose

To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP and severe acute (MRa, n=27) or chronic (MRc, n=41) MR and no coronary disease, undergoing surgical valve repair with 3 months follow-up (FU); 20 normal subjects were used as controls (N).

Methods

Speckle-tracking echocardiography was performed pre- (Bas), 1 week (1w) and 4 months (4mo) post-operatively to measure longitudinal global (GLPSS, %), regional (RPSS, %) and segmental (SPSS) peak systolic strain. Maximum and minimum mitral annulus (MA) diameters were measured with 3D echo at Bas. We also evaluated: LV end-diastolic volume index (EDVi, ml/m2); ejection fraction (EF, %); left atrial end-systolic volume index (LAVi, ml/m2); non-invasive pulmonary systolic pressure (PSP, mmHg).

Results

Risk factors (hypertension, diabetes, atrial fibrillation, smoke and previous stroke) were similar in MRc and MRa. At Bas EDVi was larger by definition in MRc (MRc: 102±21, MRa: 67±10 ml/m2, p<0.001) as LAVi (101±46 vs 76±31 ml/m2, p=0.035). Both EF (65±8 vs 64±8 ml/m2) and GLPSS (−20±4 vs −21±5%) were normal, but RPSS was reduced, only at the base (−13±6 vs −13±6%, p= ns; N: −18±2, p<0.03 vs MRc and MRa) in MRc and MRa, with reduced SPSS localized at anterior, lateral and posterior – but not septal – segments. At 1w, EF decreased in both MRc (47±14%, p<0.001 vs Bas) and MRa (56±10%, p=0.014 vs Bas), together with GLPSS (MRc: −11±4%, p<0.001 vs Bas; MRa; −13±4, p<0.001 vs Bas) driven by a prevalent marked decrease in RPSS (MRc: −7±4%, p<0.001 vs Bas; MRa; −8±5, p<0.001 vs Bas) of the LV base. All patients were alive at 3 months with no MACEs, similar reduction of mean MR grade (MRc: 4±0 to 1.9±0.7, p<0.001; MRa: 3.9±0.3 to 0.9±0.9, p<0.001) and PSP (MRc: 50±23 to 29±5 mmHg, p<0.001; MRa: 42±22 to 32±6 mmHg, p=0.039), normal EDVi (MRc: 70±27, MRa: 49±10 ml/m2), dilated LAVi (MRc: 101±46, MRa: 54±13 ml/m2), and reduced GLPSS (MRc: −12±5%, p<0.001 vs Bas; MRa; −15±3, p=0.001 vs Bas) and base RPSS (MRc: −7±6%, p=0.004 vs Bas; MRa; −10±4, p= ns vs Bas). At multivariate analysis, regional dysfunction was not related to the prolapsing scallop, presence of flail, commissure involvement, dimension and geometry of the MA, EF or pulmonary pressures.

Conclusions

In patients with MVP and severe MR, there is a specific regional longitudinal dysfunction pattern prevalent at the LV base which may be related to the duration of MR but not to annular dilatation or morphology of the prolapsing leaflets. The dysfunction worsens greatly following acute reduction of preload after surgical repair and is still significant at 4mo FU.

Funding Acknowledgement

Type of funding source: None

P1754 Regional left ventricular longitudinal myocardial dysfunction in mitral valve prolapse could be primary

Background

Regional left ventricular dysfunction in patients with mitral valve prolapse (MVP) and normal ejection fraction has been described by different Authors, and recent data point to a dysfunction (prevalently longitudinal strain) of the myocardium of the LV base secondary to dilatation of the mitral annulus.

Purpose

To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP, severe regurgitation and normal global systolic function, compared to patients with equivalent degree of regurgitation but functional etiology (FMR).

Methods

Speckle-tracking echocardiography was performed in 30 controls (N), and in severe primary (MVP, n= 50) or functional (FMR, n= 20) mitral regurgitation, to measure global, regional and segmental longitudinal peak systolic strain (LPSS, %), and time delay of peak maximum strain (TTPd, ms, calculated as time to peak maximum strain - time of aortic valve closure). Maximum and minimum mitral annulus diameters and area were measured with 3D echo. We also evaluated as recommended: LV end-diastolic volume index (EDVi, ml/m2), ejection fraction (EF, %), and left atrial end-systolic volume index (LAESVi, ml/m2) with 2D echo; LV stroke volume index, and non-invasive pulmonary systolic (PSP, mmHg) and diastolic pressures (PDP), mmHg) with Doppler echo.

Results

Age, heart rate, BSA and systolic blood pressure were similar between groups. Atrial fibrillation was present in 34% of MVP and 71% of FMR patients. LV EF was normal in MVP and reduced in FMR (43 ± 14 % vs N, p<.001). LV EDVi (MVP: 77 ± 20 ml/m2; FMR: 107 ± 35, both p<.001 vs N) and LAESVi (MVP: 91 ± 26 ml/m2; FMR: 80 ± 30, both p<.001 vs N) were similarly increased (volume overload) in MVP and FMR, as were PSP (MVP: 42 ± 23 ml/m2; FMR: 52 ± 25, both p<.001 vs N) and PDP (MVP: 16 ± 6 ml/m2; MVP: 15 ± 5, both p<.001 vs N). In FMR, LPSS was reduced globally (-12.8 ± 3.3, p<.001 vs N and MVP) and similarly at LV base, papillary and apical levels. In contrast, in MVP global (-19.4 ± 3.7%) and apical (-23.4 ± 4.5%) LPSS were normal, whereas LV base (-12.3 ± 5.8%, p=.003 vs N) and papillary (-17.1 ± 4%, p=.024 vs N) LPSS were reduced; further, LPSS reduction was localized to the anterior (-16 ± 4, p=.028 vs N), lateral (-17 ± 5, p=.006 vs N) and posterior (-16 ± 6, p=.007 vs N) segments, and was associated with an increased TTPd in the same segments in MVP but not in FMR patients. At multivariate analysis, degree and localisation of regional myocardial dysfunction in patients with MVP was not related to the prolapsing scallop, dimension of the mitral annulus, degree of volume overload or pulmonary pressures, or stroke volume index.

Conclusions

In patients with MVP, severe regurgitation and normal EF, there is a specific dysfunction pattern of regional LV longitudinal function which appears to be primary and not dependent on the degree of preload increase, mitral annulus dilatation, or localization of the prolapsing scallop.

Does the Ventrica Magnetic Vascular Positioner (MVP®) for Coronary Artery Bypass Grafting Significantly alter Local Fluid Dynamics? a Numeric Study

Objective

Automatic devices have been recently introduced to make the anastomosis procedure quick and efficient when creating a coronary bypass on the beating heart. However, the implantation of these devices could modify the graft configuration, consistently affecting the hemodynamics usually found in the traditional anastomosis. As local fluid dynamics could play a significant role in the onset of vessel wall pathologies, in this article a computational approach was designed to investigate flow patterns in the presence of the Ventrica magnetic vascular positioner (Ventrica MVP®) device.

Methods

A model of standard hand-sewn anastomosis and of automated magnetic anastomosis were constructed, and the finite volume method was used to simulate in silico realistic graft hemodynamics. Synthetic analytical descriptors - i.e., time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and helical flow index (HFI) - were calculated and compared for quantitative assessment of the anastomosis geometry hemodynamic performance.

Results

In this case study, the same most critical region was identified for the 2 models as the one with the lowest TAWSS and the highest OSI (TAWSS=0.229, OSI=0.255 for the hand-sewn anastomosis; TAWSS=0.297, OSI=0.171 for the Ventrica MVP®). However, the shape of the Ventrica MVP® does not induce more critical wall shear stresses, oscillating flow and damped helicity in the graft fluid dynamics, as compared with conventional anastomosis.

Conclusions

We found that the use of the Ventrica MVP® for the case study under investigation was not associated with more critical fluid dynamics than with conventional hand-sewn anastomosis. Thereby, the device could facilitate beating heart and minimally invasive coronary artery bypass grafting without increasing local hemodynamic-related risks of failure. (Int J Artif Organs 2007; 30: 628–39)

Enhanced recovery after surgery (ERAS) pathway vs traditional care in laparoscopic rectal resection: a single-center experience

BACKGROUND

The aim of this study was to compare the outcome of an enhanced recovery after surgery (ERAS) pathway with traditional perioperative care in laparoscopic rectal resection.

METHODS

A retrospective analysis of prospectively collected data was conducted. Single-center consecutive patients who underwent laparoscopic rectal surgery after an ERAS program were compared with patients who received traditional care over an 8-year period. Primary and total length of stay, and readmission, morbidity and mortality rates were analyzed. For ERAS group, the actual adherence to protocol was also evaluated.

RESULTS

Two hundred and ninety-seven patients, 162 in the ERAS group and 135 in conventional care, were studied. Median primary and total length of stay were significantly shorter in the ERAS group (9 vs 12 days; p = 0.0001; 10 vs 12 days; p = 0.01; respectively). The ERAS group experienced a faster recovery of bowel function than the traditional care group (p = 0.0001). A similar morbidity rate was observed in the two groups (32.3 % in ERAS vs 36.1 % in traditional care p = 0.41). Readmission rates were 4.9 % in the ERAS versus 1.5 % in the traditional care group (p = 0.19). There was no mortality in either group. Overall mean compliance with the ERAS protocol was 85.7 % (range 54.4-100 %).

CONCLUSIONS

The introduction of the ERAS protocol in laparoscopic rectal resection led to a reduction in primary and total length of hospital stay without an increase in morbidity or readmission rates when compared to traditional care.

In vitro hemodynamics and valve imaging in passive beating hearts

Due to their high complexity, surgical approaches to valve repair may benefit from the use of in vitro simulators both for training and for the investigation of those measures which can lead to better clinical results. In vitro tests are intrinsically more effective when all the anatomical substructures of the valvular complexes are preserved. In this work, a mock apparatus able to house an entire explanted porcine heart and subject it to pulsatile fluid-dynamic conditions was developed, in order to enable the hemodynamic analysis of simulated surgical procedures and the imaging of the valvular structures. The mock loop's hydrodynamic design was based on an ad-hoc defined lumped-parameter model. The left ventricle of an entire swine heart was dynamically pressurized by an external computer-controlled pulse duplicator. The ascending aorta was connected to a hydraulic circuit which simulated the input impedance of the systemic circulation; a reservoir passively filled the left atrium. Accesses for endoscopic imaging were located in the apex of the left ventricle and in the aortic root. The experimental pressure and flow tracings were comparable with the typical in vivo curves; a mean flow of 3.5±0.1l pm and a mean arterial pressure of 101±2 mmHg was obtained. High-quality echographic and endoscopic video recordings demonstrated the system's excellent potential in the observation of the cardiac structures dynamics. The proposed mock loop represents a suitable in vitro system for the testing of minimally-invasive cardiovascular devices and surgical procedures for heart valve repair.

Protection of intestinal anastomosis with biological glues: an experimental randomized controlled trial

BACKGROUND

The aim of the study was to compare the degree of healing and air tightness of hand-sewn colonic anastomoses provided by different biological glues.

METHODS

Thirty colonic anastomoses were fashioned in ten rabbits, at 5, 10, 15 cm from the ileocecal valve, with 4/0 PDS running sutures. Each suture was randomized to treatment with fibrin sealant (Tissucol®), a synthetic glue (Coseal®), or nothing (control). After 15 days, the rabbits were killed and the anastomoses examined for their integrity and resistance to bursting. The van der Hamm scale was used to evaluate postoperative adhesions. A blind histological evaluation of the newly formed tissue was made (Ehrlich-Hunt scale).

RESULTS

Two rabbits developed an intraabdominal abscess, one in the control anastomosis group without glue. Postoperative adhesions were present in all animals. Median anastomosis bursting pressures were 0.9 atm in all three groups: Tissucol, Coseal, and control. Pressure values were 0.9, 1.0, and 0.9 atm in the three different proximodistal sites, respectively. A trend toward an increased resistance was observed in the glued anastomosis, although this was not significant. Lymphocyte infiltration, fibroblast activity, blood vessel density, and collagen deposition were lower in controls. Anastomoses treated with Tissucol had the highest lymphocyte infiltration level. The Coseal group developed the highest rates of fibroblast activity, collagen deposition, and blood vessel neogenesis.

CONCLUSION

The use of biological glues did not result in a statistically significantly increased bursting resistance. Histological evaluation demonstrated more intense tissue neoformation in the glue groups, particularly in the Coseal group. The role of biological glues in decreasing the leakage rate of intestinal anastomoses is uncertain, and larger trials using different protective agents are warranted.

Fecal incontinence: up to date on pathophysiology and treatment

This study analyzes the most recent insight into the pathophysiology of fecal incontinence considering each of the factors contributing to the mechanism of fecal continence both during urgency to defecate and in resting state. In fact different types of incontinence are caused by different damage to one or more of these physiologic factors. The second part of the study focuses on the therapeutic choices of fecal incontinence. The recent introduction of sacral nerve electrostimulation and the progressive broadening of its clinical indications is progressively replacing and challenging other traditional surgical techniques because of their disappointing long-term results and because they are much more invasive. An emerging new treatment based on the injection of anal bulking agents is nowadays even more preferred for the less severe cases of fecal incontinence. An increasing number of materials is now proposed by the industry in order to identify the best biocompatible material to be injected trans-anally. Traditional surgery could be reserved for patients non-responding to these new treatments.

Should pregnancy be considered a risk factor for aortic dissection? Two cases of acute aortic dissection following cesarean section in non-Marfan nor bicuspid aortic valve patients

Acute aortic dissection in pregnancy is a rare event and rarer still in healthy young women; however, women with a bicuspid aortic valve or the Marfan syndrome are at a higher risk of dissection. The relationship between pregnancy and aortic dissection is still unclear. We describe the cases of two women with no history of cardiovascular disease who developed an acute aortic type A dissection within a few days after term delivery. Surgical repair was performed with ascending aorta replacement and aortic valve sparing. In both cases, the dissection was diagnosed within a few days following cesarean section done neither because of fetal or maternal distress. To date, only one case of type A and two cases of type B aortic dissection following cesarean section have been reported. Compared with spontaneous delivery, scheduled cesarean section, as in our cases, allows for better control of hemodynamic parameters and should protect against aortic dissection. Postoperative screening for inherent connective tissue disorders detected no mutations within the fibrillin and collagen gene chromosome in either patient. Postoperative recovery was uneventful, and the patients were discharged on postoperative days 7 and 8, respectively.

Myocardial revascularization with multiple arterial grafts: comparison between the radial artery and the right internal thoracic artery

BACKGROUND

Bilateral internal thoracic artery (ITA) harvesting is significantly underused, whereas the radial artery is being used with increasing frequency. We have retrospectively analyzed perioperative and short-term outcomes of patients receiving a radial artery versus those receiving a right ITA as a second arterial graft.

METHODS

Between February 1999 and May 2000, 250 patients underwent coronary artery bypass grafting using the radial artery (156 patients) or the right ITA (94 patients) in combination with the left ITA and, when required, the saphenous vein.

RESULTS

There was a higher prevalence of risk factors in the radial artery group. More coronary artery bypass graftings (p < 0.001) were performed with the radial artery. Operative mortality was not different (p = not significant). In the right ITA group there was more bleeding (p < 0.001) and a longer hospital stay (p < 0.001). Mean follow-up was 8.1 +/- 3.9 months. The probability of survival was similar (p = not significant).

CONCLUSIONS

The radial artery can extend the benefits of multiple arterial grafting to those patients who are usually excluded from bilateral ITA harvesting because of multiple risk factors. Perioperative and short-term results are good.

[Left atrium rupture after non-penetrating injury to the back]

Survival after cardiac rupture associated with blunt thoracic trauma is very uncommon. In these patients successful management demands a high index of suspicion of cardiac injury. A case of a 24-year-old woman who presented unconscious and shocked in the emergency room after motorcycle trauma strictly limited to her back is reported. Rib and sternal fractures were absent; the typical signs of cardiac tamponade were not found. Therefore the suspicion of cardiac chamber rupture was not immediate and the cardiologist was consulted after several diagnostic exams. Transthoracic echocardiography showed a pericardial effusion with clots and initial cardiac tamponade. The patient was transferred to the operating room and a large hemopericardium was disclosed. Two lacerations were noticed: the first pericardial, near the inferior vena cava, and the second one in the posterior wall of the left atrium. It is possible that the associated pericardial tear and pericardial clots could have contributed to survival. After surgical repair, carried out during cardiopulmonary bypass, the recovery was quick and complete. This case report confirms the possibility of heart chamber rupture after blunt chest trauma even in the absence of obvious thoracic lesion and it shows that the presentation could be very insidious without a "classic" clinical picture of cardiac tamponade. In front of an unexplained shock after nonpenetrating thoracic trauma, a rupture of the heart chambers should be suspected and echocardiography is mandatory. In the emergency room environment pericardiocentesis should be performed only with a quickly available cardiac surgery or in the presence of overwhelming hemodynamic failure.

Treatment of anterior mitral leaflet prolapse: chordal suture plication and free-edge remodeling in 34 patients

In this study are considered the short-middle term results of anterior mitral leaflet prolapse repair obtained by means of a personal operative technique: chordal shortening and free edge remodeling. In our institution since 1993 34 consecutive patients with degenerative myxomatous mitral regurgitation, (mean age 63.3 years, range 25 to 83 years), underwent surgery. Before the operation 22 patients (64.7%) were in NYHA functional class III or IV. Mitral insufficiency, evaluated by echocardiogram, was severe in all patients; a prolapse of only anterior leaflet was present in 10 patients, both leaflets prolapsed in the others. Patients with chordal rupture of anterior mitral leaflet were excluded. Anterior mitral leaflet prolapse repair was performed with two continuous sutures including the free edge as well as the chordae for a variable length (2 mm up to 5 mm) depending on the degree of the elongation. A concomitant posterior leaflet quadrangular resection was performed in 24 patients (70.5%), and the procedure was almost always completed by a posterior suture annuloplasty reinforced by a glutaraldehyde-tanned strip of autologous pericardium. There were no perioperative deaths. The postoperative course was uneventful in all cases, and there were no hospital deaths. Postoperative echocardiographic evaluation showed satisfactory valve function. The mean valvular regurgitation before surgical procedure was 3.67 +/- 0.4, after repair 0.30 +/- 0.5 (p < 0.01). Follow-up was completed in all patients (mean 16.5 months) with no late deaths. One patient required early reoperation for recurrent mitral regurgitation resulting for a recurring anterior leaflet prolapse. We conclude that this technique is a safe, effective and easy procedure for the repair of anterior mitral leaflet prolapse without rupture. Nevertheless, a larger number of patients and a longer follow-up are required to confirm our results.

Myocardial revascularization in patients with ischemic cardiomyopathy: functional observations

OBJECTIVE

A prospective angiographic study was undertaken to investigate, with an objective analysis, the global and regional wall response to myocardial revascularization.

METHODS

Thirty-one patients (30 men and 1 woman, mean age, 61 years) with a left ventricular ejection fraction of less than 0.30 were admitted to our institution between 1992 and 1995 for two- or three-vessel coronary artery disease requiring myocardial revascularization. All patients underwent isolated coronary artery bypass grafting and were studied 3 months later with angiography. Preoperative and postoperative wall motion were analyzed using special software that computed a segmental left ventricular ejection fraction, generating a segmental score. Computerized analysis allowed us to distinguish patients with diffuse hypokinesis and a symmetric contraction pattern from patients with akinesis involving at least two segments and an asymmetric contraction pattern.

RESULTS

There were no operative deaths and no patient required intraaortic balloon counterpulsation. One patient had postoperative enzymatic evidence of myocardial infarction. Postoperative angiography showed a graft patency rate of 84%. Global analysis showed a small but significant rise in the left ventricular ejection fraction (0.25 +/- 0.51 to 0.31 +/- 0.70, p < 0.001) and a fall in the left ventricular end-diastolic pressure (23.7 +/- 10 to 16.5 +/- 9 mm Hg, p < 0.01). Mean scores always have been lower after the operation than before it, with the best results obtained for the apex and the worst for the anterobasal segment. The group with a symmetric contraction pattern showed a trend toward a better hemodynamic response than the group with an asymmetric contraction pattern. Regression analysis revealed two important predictors of segmental functional improvement: (1) the absence of an echocardiographic scar, and (2) the presence of a collateral circulation.

CONCLUSIONS

Coronary artery bypass grafting produced a small but substantial improvement in patients with ischemic cardiomyopathy. The greater benefit occurred in patients with a symmetric contraction pattern. The absence of an echocardiographic scar and the presence of a collateral circulation predicted segmental functional improvement.

[Antioxidant action of Foy in an experimental model of hypergeneration of oxygen free radicals]

BACKGROUND

Several trials have just demonstrated the therapeutic efficacy of gabexate mesylate (Foy). For this drug numerous mechanisms of action have been postulated; protease inhibition, direct or indirect lysosomal membrane stabilization, etc. The aim of this study has been to verify if Foy would express antioxidant properties against free radical overgeneration, responsible for the increase in microvascular permeability which represents one of the most important pathogenetic phenomenon of any condition of shock. A mixture of hypoxanthine-xanthine oxidase has been used to obtain a generation of oxygen free radicals in vivo.

METHODS

Experiments were performed on the mesocecum of male Wistar rats; fluorescent labelled bovine albumin has been injected intra-arterially to evaluate the capillary permeability and the mesocecum microcirculation has been observed by fluorescent microscopy. The control group received saline i.v., the second group received topically applied on the mesocecum a mixture of 0.96 mM hypoxanthine and 0.05 UI/ml xanthine oxidase; the third and the fourth groups were pretreated respectively with a topical application and continuous infusion of a Foy 1% solution (50 ml/kg/min). To evaluate capillary permeability and to quantify the degree of extravasation by counting the number of leaky sites, labelled bovine albumin was injected i.a. and mesocecum was observed with fluorescent microscopy for 2 hours.

RESULTS AND CONCLUSION

Gabexate mesilate (Foy) exerts its efficacy preventing the increase in capillary permeability provoked by an overgeneration of free radicals; it could express antioxidant properties.

[Antioxidant action of gabexate mesilate (Foy) in an experimental model of endotoxic shock]

BACKGROUND

Circulatory shock, especially endotoxin shock, is characterized by the release of a large number of mediators, among which proteases play a key role. The production of oxygen free radicals into the extracellular space and the increase of capillary permeability is one of the most important consequences of that phenomenon. In order to evaluate the efficacy of gabexate mesilate (Foy) in preventing such increase of microvascular permeability, an experimental model of endotoxin shock was used.

MATERIALS AND METHODS

Experiments were performed on the mesocecum of male Wistars rats, fluorescent labeled bovine albumine was injected intrarterially to evaluate the capillary permeability and the mesocecum microcirculation was observed by fluorescent light. The control group received saline i.v.; the II group received a DL 100 of E. coli endotoxin (DIFCO 0111: B4); the III and the IV group received a continuous infusion or topical application of gabexate mesilate respectively, before the administration of endotoxin. To evaluate capillary permeability and to quantify the degree of extravasion by counting the number of leaky sites, fluorescent labelled bovine albumin was injected i.v. and mesocecum was observed with fluorescent microscopy for 2 hours.

RESULTS AND CONCLUSIONS

Capillary permeability did not increase in control rats; it largely increased in rats receiving endotoxin i.v. but it did not almost increased in rats receiving gabexate mesilate (Foy) that prevents the increase of capillary permeability that was observed in the group treated with endotoxin alone.

Improvement of cardiac function by allopurinol in patients undergoing cardiac surgery

Allopurinol reduces formation of cytotoxic free radicals during myocardial ischemia/reperfusion in animals. To evaluate the effect of allopurinol on cardiac performance and metabolism after coronary bypass in humans, we divided 33 patients into two groups: 15 patients (controls) received no allopurinol and 18 patients received 200 mg allopurinol intravenously (i.v.) 1 h preoperatively. Hemodynamic measurements were made with a triple-lumen thermodilution pulmonary artery catheter before cardiopulmonary bypass (CPB), 30 min after completion of CPB and 6 h later in the intensive care unit (ICU). A catheter placed into the coronary sinus was used for blood sampling for measurement of lactate and creatine phosphokinase MB. Peripheral blood was obtained for measurement of xanthine oxidase activity (XO), uric acid, and thiol groups. A myocardial biopsy was taken for measurement of thiol group content and XO before CPB and after heparin neutralization with protamin (a few minutes after CPB). Treated patients had better recovery of cardiac output (CO) and left ventricular stroke work (LVSW) 30 min and 6 h after completion of CPB than did controls. Allopurinol significantly reduced plasma XO. Plasma concentrations of uric acid increased significantly in both groups 30 min after completion of CPB, but the increase in controls was greater (p < 0.02) than with allopurinol. Thiol group levels increased (p < 0.05) only in controls. Our results demonstrate improvement of cardiac function in coronary artery bypass surgery with allopurinol that is related to its metabolic effects consistent with protection against XO catalyzed free radical-mediated injury.

[Increase in capillary permeability induced by endotoxin: protection with antioxidants and glutathione]

Endotoxin administration increases capillary permeability in experimental animals and this is one of the most relevant events in the pathophysiology of endotoxin shock; the aim of the present experiment was to demonstrate that the action of endotoxin on capillary permeability is due to oxygen-free radicals generation. Experiments were performed on the mesocecum of male Wistar rats; fluorescent labeled bovine albumin (FITC-BSA) was injected intra-arterially to evaluate the capillary permeability; the mesocecum microcirculation was observed by fluorescent light. Permeability was quantified by changes in the number of leaky sites at 10 minute intervals for an hour. The effects of Endotoxin (DIFCO 0111:B4, 30 mg/kg i.a.) were assessed in rats receiving 1) saline, 2) reduced glutathione (250 or 500 mg/kg i.p.), 3) three different nitrones (PBN, DMPO, POBN) (6.25 mg/kg i.p.) whose action is to "trap" oxygen radicals. Capillary permeability largely increased in a few minutes in control rats but it was quite unaffected in rats receiving glutathione or nitrones. As a conclusion the increased capillary permeability observed after endotoxin injection in rats may be due to an oxygen-radicals generation.

Cardiac surgery in HIV-positive intravenous drug addicts: influence of cardiopulmonary bypass on the progression to AIDS

In the last years the number of HIV-positive patients needing cardiac surgery has greatly increased. Cardiopulmonary bypass is suspected to have a role in the progression of HIV-infection to acquired immunodeficiency syndrome (AIDS). From October 1988 to December 1990, 6 intravenous drug addicts underwent cardiac surgery for infective endocarditis at our Department. Preoperative and postoperative absolute lymphocyte T-helper (CD4) and T-suppressor (CD8) counts did not show a close association between the temporary lymphopenia induced by cardiopulmonary bypass and progression to AIDS.

[Surgical treatment of diffuse coronary disease]

Considering the morphological aspects of diffuse coronary disease one must argue that, in their presence, myocardial revascularization can be performed only by coronary endarterectomy (EA), together with conventional bypass grafting. A variety of EA techniques ("blind" and "open" EA) are analyzed. Indications, long and short-term results (operative risks, symptomatic improvement, grafts patency) of each procedure are evaluated on the basis of the current experiences. We conclude that EA is a valuable complement to coronary artery bypass grafting which allows: a) a larger number of conventionally inoperable patients to benefit from the surgical treatment; b) more complete revascularization in patients with diffuse coronary disease.

Coronary “open” endarterectomy and reconstruction: short- and long-term results of the revascularization with saphenous vein versus IMA-graft

From June 1984 to December 1990, 96 patients underwent "open" coronary endarterectomy and reconstruction. In 50 patients (group 1), a saphenous vein (SV) graft was used to reconstruct and bypass 54 coronary vessels. In 46 patients (group 2), 46 coronary vessels were reconstructed with an SV patch and then bypassed with the internal mammary artery (IMA): Seventy-four LAD coronary arteries (36 in group 1 and 38 in group 2) were treated with these procedures. Operative mortality was 8% in group 1 and 2.1% in group 2. Five patients (10%) in group 1 and 1 patient (2.1%) in group 2 developed perioperative myocardial infarction. The early postoperative patency of the reconstructed vessels was 84.6% in group 1 and 92.5% in group 2. Angiographic controls were performed between 30 and 36 months after operation in 18 patients (72%) of group 1 and in 16 patients (69%) of group 2 with patency rates of 66.7% and 81.5%, respectively. A further angiographic study performed between 54 and 60 months after operation of 9/22 patients of group 1 and 5/9 patients of group 2 did not show any additional closure of the endarterectomized vessels. Three- and 5-year survival analyzed by the Kaplan-Meier method was 79.6% and 69.7%, respectively, in group 1 and 86.8% for both the 3- and 5-year survival in group 2. After a mean follow-up of 51.0 and 35.5 months, 62.8% of the surviving patients of group 1 and 75.6% of group 2 were asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial revascularization with arterial grafts alone: our experience]

Bilateral internal mammary artery (IMA) grafting is recognized as a preferred method of myocardial revascularization. However, for multivessel coronary artery disease, saphenous veins often have to be added to complete myocardial revascularization. The right gastroepiploic artery (rGEA) has been recently recognized as a suitable arterial conduit to obtain with both IMAs a complete myocardial revascularization without conventional vein graft. From December 1985 to July 1990, 87 selected patients underwent coronary artery bypass grafting using only the two IMAs and, from December 1988, the rGEA. There were a total of 220 coronary artery bypass grafts (mean 3.06/patient) and 267 coronary artery anastomoses (mean 1.21 anastomoses graft). There was one perioperative death (1.14%), 3 patients (3.5%) developed a perioperative myocardial infarction, and 7 patients (8.04%) needed a transitory inotropic pharmacological support. Two patients (2.29%) underwent reoperation for bleeding, and a third (1.14%) for sternal diastase. Fifty-five patients (63.2%) underwent postoperative angiography: 6/139 grafts (4.31%) (3 rGEA free, 2 rIMA free, 1 rIMA in situ) were occluded. After follow-up, ranging from 12 to 66 months (30.54 average), 77 patients (92.77%) were free from angina, one patient underwent reoperation 7 months later and a third died for sudden death 55 months after the operation. There were no gastric complications due to rGEA harvesting. Actually, bilateral IMA grafting is the best investment for the patient who needs myocardial revascularization. The rGEA is a promising conduit whose only concern could be the long-term patency; this will be resolved in the future. Up-to-date combined arterial graft utilizing the IMA and the rGEA can facilitate complete revascularization by arterial grafts safely and effectively.

Gastroepiploic artery free graft for coronary bypass

The internal mammary artery (IMA) is the graft of choice for CABG but has a limited number and length. For multivessel coronary disease, saphenous vein grafts have to be added but they show poorer long-term patency. Investigation to provide adjunctive reliable grafts has recently focussed on the right gastroepiploic artery (GEA) and encouraging results have been reported employing this vessel as a pedicled graft to bypass distal coronary vessels. From December 1988 to February 1989, to achieve complete myocardial revascularization with only arterial grafts we used a GEA free graft in combination with the two IMAs in 20 consecutive patients under 70 years of age undergoing elective surgery. Before starting, histological studies were carried out and a significant similarity between IMA and GEA was found. In the 20 patients, 76 coronary anastomoses were performed (3.8 bypasses/patient), the GEA graft revascularized the right coronary artery in 9 patients, the circumflex in 8 patients and the anterior descending and/or diagonal in 3 patients; in 7 patients the GEA graft was used for sequential anastomoses. No perioperative deaths, no myocardial infarctions and no gastroenterological complications occurred. Coronary angiographic postoperative control showed 20/20 patent GEA grafts. After follow-up ranging from 7 to 9 months, all patients are free from angina. The GEA free graft is not difficult to harvest, is easier than the pedicled GEA graft to handle in the pericardium and is suitable for sequential anastomoses. The use of GEA graft however increases the complexity of bypass operations.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated atresia of the left main coronary artery in an adult

A 49-year-old woman with isolated atresia of the left main coronary artery is presented. The patient who suffered from angina underwent myocardial revascularization 14 years after the onset of symptoms. A left internal mammary artery to left anterior descending coronary artery bypass was performed. Twenty months after the operation, the patient is free from angina and leads a normal life. The clinical features, diagnosis and management of the left main coronary atresia in adults are discussed.