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Biomedical subjects

M A Schepens

Publications and source records attributed to M A Schepens.

At least 19 recordsLinked to original sources
PubMed2005

Clinical prospective study of biochemical markers and evoked potentials for identifying adverse neurological outcome after thoracic and thoracoabdominal aortic aneurysm surgery.

BACKGROUND: Neurological deficit after repair of a thoracic or thoracoabdominal aortic aneurysm (TAA/TAAA) remains a devastating complication. The aim of our study was to investigate the clinical value of biochemical markers [S-100B, neurone-specific enolase (NSE) and lactate dehydrogenase (LD)], evoked potentials and their combinations for identifying adverse neurological outcome after TAA/TAAA surgery. METHODS: From 69 patients, cerebrospinal fluid and blood samples for biochemical analysis were drawn after the induction of anaesthesia, during the cross-clamp period, 5 min, 2, 4, 6, 8, and 19 h, respectively, after reperfusion. In addition, continuous perioperative recording of motor-evoked potentials after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potentials was carried out. Furthermore, neurological examinations were performed. RESULTS: In patients with a defined decrease in lower extremity tcMEP during the cross-clamp period, we found that combinations of the serum concentrations of S-100B and tcMEP ratios at 4, 6, and 8 h after reperfusion had a positive and negative predictive value of 100% in predicting adverse neurological outcome after TAA/TAAA surgery. Furthermore, combinations of the serum concentrations of S-100B and NSE or LD at 19 h after reperfusion had both a positive and negative predictive value of 100% in identifying patients with adverse outcome after TAA/TAAA repair. CONCLUSIONS: TcMEP monitoring during TAA/TAAA surgery seems to be an effective but not completely sufficient guide in our protective multi-modality strategy. Combinations of the serum concentrations of S-100B and tcMEP ratios during the early reperfusion period might be associated with adverse neurological complications. Furthermore, biochemical markers could detect central nervous system injury on the first postoperative day and may have prognostic value.

Adult↗
PubMed2003

[Ischemia of the lower limbs as a symptom of acute dissection of the ascending aorta].

A 27-year-old man, two 54-year old men and a 64-year-old woman presented with aspecific symptoms: acute pain and tingling in the shoulders plus paraplegia; exertional dyspnoea and tingling in both feet for the past week; increasing shortness of breath and cold, pale legs and feet for the past week; acute retrosternal pain, incontinence and paraparesis. The cause was dissection of the ascending aorta (type A). Following the operation, the legs were amputated because of ischaemia. The 27-year-old man and one of the 54-year-old men died; the other two patients made a satisfactory recovery. Acute type-A aortic dissection is a life-threatening disease that must be recognised early because it is an absolute indication for emergency surgery. The initial manifestation of type-A dissection may be very aspecific. Post-operative lower limb ischaemia, as the first symptom of this disease, is rare and usually disappears after surgery for type-A dissection. In some cases, however, ischaemia persists and alters the post-operative course dramatically.

Adult↗
PubMed2002

Stroke related to cardiac and/or aortic surgery: an overview.

In recent years there has been an increasing awareness of atheromatous disease of the aorta and its role has become more evident in relation to neurologic deficits following cardiac and aortic surgery. Specific surgical events can release emboli blocking cerebral arteries and cause catastrophic neurologic sequelae plagueing the patients, their families and the health care system. The extent of the problem is illustrated and the pathophysiologic mechanisms are explained. Special attention is given to the calcified aorta and the preventive actions that can be undertaken by the surgeon to avoid cerebral damage. Aortic surgery cannot be separated from cardiac surgery and therefore specific aortic problems related to cerebral damage are highlighted such as aortic dissection and aortic arch replacement.

Age Distribution↗
PubMed2001

Risk stratification in acute type A dissection: proposition for a new scoring system.

BACKGROUND: The aim of this study was to develop a scoring system for operative mortality of patients with acute type A aortic dissection. METHODS: Between 1974 and 1999, a total of 252 patients were operated on for an acute type A aortic dissection. We reviewed retrospectively preoperative and intraoperative records to conduct an analysis of risk factors associated with surgery. Multivariate analysis was used to predict operative mortality and to provide a preoperative risk profile of each individual patient that could be used for future patients. RESULTS: Operative mortality was 25.0% (n = 63). A logistic regression model with three explanatory variables to predict operative death showed a good fit: the risk factors associated with operative mortality were preoperative cardiopulmonary resuscitation (p = 0.0013, odds ratio = 15.7) and iatrogenic dissection (p = 0.0014, odds ratio = 9.8). Drained pericardial tamponade (p = 0.0386, odds ratio = 0.12) appeared to be a protective factor associated with decreased mortality. CONCLUSIONS: Because existing scoring systems do not fit this pathologic condition, we propose the use of this Antonius Dissection Scoring System, based on the logistic regression model, to predict the chances of operative mortality for each patient before operation. The survival of patients with concomittant pericardial tamponade may benefit from pericardial drainage.

Acute Disease↗
PubMed2001

Thoracic and thoracoabdominal aortic aneurysm repair: use of evoked potential monitoring in 118 patients.

PURPOSE: Paraplegia is the most dreaded and severe complication of surgery on the descending thoracic aorta (TAA) and thoracoabdominal aorta (TAAA). The functional integrity of the spinal cord can be monitored by means of intraoperative recording of myogenic-evoked responses after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potential (SEP) monitoring. In this study, we evaluated the results of evoked potential monitoring and the adequacy of the strategy followed. METHOD: The spinal cord of 118 patients (78 men; age, 65 +/- 12 years; 79 TAAAs, 39 TAAs) undergoing surgery on the TAA or TAAA was monitored with tcMEP and SEP. Spinal cord protection was achieved by means of a multimodality approach: moderate hypothermia (32 degrees C rectal temperature), continuous cerebrospinal fluid drainage to keep the pressure less than 10 mm Hg, reimplantation of intercostal arteries, left ventricular bypass grafting, and staged clamping. In the case of evoked potential changes more than 50% of baseline, the strategy was adjusted: reattachment of more segmental arteries when technically feasible, higher distal and proximal perfusion pressures, and enhanced cerebrospinal fluid drainage. RESULTS: Forty-two of 118 patients (35.6%) had a more than 50% of baseline tcMEP reduction during cross-clamping. At this point, only 5 of those 42 cases were also associated with SEP reduction of more than 50% of baseline. On the basis of the tcMEP findings, the strategy was adjusted. Five patients had postoperative paraplegia (4.2%). CONCLUSION: tcMEP monitoring seems to be a useful adjunct of the protective techniques and may cause substantial adjustments in strategy, reducing the incidence of postoperative paraplegia.

Aged↗
PubMed2000

[Reimplantation of aortic valve; preliminary results in 13 patients].

OBJECTIVE: To evaluate our initial experience with the reimplantation technique of the aortic valve. DESIGN: Retrospective. METHOD: From January 1st 1998 to January 31st 2000, 13 patients were operated on by the technique as described by David. Mean age was 52.2 years (SD: 11). Median preoperative New York Heart Association (NYHA) functional class was 2/4 and median preoperative degree of aortic regurgitation was 3/4. Surgical indications were initially limited to aneurysmal disease of the aortic root (n = 6) and ascending aorta (n = 4), all complicated by aortic regurgitation. Later on, we also applied the technique in type A aortic dissection (n = 3). The repair was evaluated peroperatively by transoesophageal and postoperatively, by transthoracic echocardiography. The patients were followed postoperatively in the outpatient department. RESULTS: No technical problems arose that necessitated change or adjustment of the technique. Mean cardiac arrest time was 184 min (SD: 40) and cardiopulmonary bypass time 254 min (SD: 74). The primary aetiology on histopathological examination was medial necrosis in 5 patients and degenerative disease in the others. There was no early nor late mortality and none of the patients was reoperated upon the aortic root. Follow-up was complete at a mean of 12.3 months (SD: 8). Median aortic regurgitation at follow-up was 0.5 (p = 0.0001 versus preoperative) and median NYHA functional class at follow-up was 1 (p = 0.02 versus preoperative). CONCLUSION: David's aortic valve reimplantation technique was carried out with a low surgical risk and a low degree of residual aortic regurgitation in aneurysm of the aortic root, aneurysm of the ascending aorta and type A dissection with major destruction of the aortic root.

Adult↗
PubMed2000

Durability of aortic valve preservation and root reconstruction in acute type A aortic dissection.

BACKGROUND: The aim of this study was to determine the durability of aortic valve preservation and root reconstruction in type A aortic dissection with involvement of the aortic root. METHODS: From November 1976 to February 1999, 246 patients underwent surgical treatment for acute type A aortic dissection at our institution. In 121 patients (49%), all with acute type A dissection and aortic root involvement, the aortic valve was preserved and one or more of the sinuses of Valsalva were reconstructed. The mean age of this group was 59 +/- 11 years and 70 (58%) were men. Thirty patients (25%) were operated in cardiogenic shock. Criteria for aortic root reconstruction were technical feasibility and surgeon preference. Techniques used for reconstruction were valve resuspension in all patients and additional reinforcement of the aortic root with Teflon (L.R. Bard, Tempe, AZ) felt (n = 21), gelatin-resorcinol-formaldehyde-glue (GRF-glue, Fii, Saint-Just-Malmont, France) (n = 103), or fibrinous glue (Tissu-col, Immuno AG, Vienna, Austria) (n = 5). Mean follow-up was 43.5 +/- 46 months. RESULTS: The operative mortality was 21.5% (n = 26). Actuarial survival was 72% +/- 4%, 64% +/- 5%, and 53% +/- 6% at 1, 5, and 10 years, respectively. Median aortic regurgitation in patients with retained native aortic valve at follow-up was 1+. All root reoperations included aortic valve replacement (n = 12). Freedom from aortic root reoperation was 95% +/- 2% at 1 year, 89% +/- 4% at 5 years, and 69% +/- 9% at 10 years. The incidence of aortic root reoperation was 23%, 11%, and 40%, respectively, when Teflon felt, GRF-glue, and fibrinous glue were used for root reconstruction. Multivariate Cox proportional hazard analysis revealed the use of fibrinous glue (RR = 8.7; p = 0.03) as well as the presence of an aortic valve annulus more than 27 mm (RR = 4.2; p = 0.04) as independent risk factors for aortic root reoperation. CONCLUSIONS: Aortic valve preservation in acute type A dissection provides relatively durable results. The use of fibrinous glue for root reconstruction seems to compromise the long-term durability of the repair compared with Teflon felt and GRF-glue. A dilated aortic annulus requires a more extensive root procedure.

Actuarial Analysis↗
PubMed2000

Bilateral antegrade selective cerebral perfusion during surgery on the proximal thoracic aorta.

OBJECTIVE: To assess risk factors for hospital death and neurologic outcome after surgery on the proximal thoracic aorta using moderate hypothermic circulatory arrest and bilateral antegrade selective cerebral perfusion. METHODS: From October 1995 through June 1999, 163 patients with a mean age of 63+/-11 years underwent surgery using bilateral antegrade selective cerebral perfusion. Degenerative aneurysms (55%) and acute type A dissection (28%) were the predominant indications for operation. Forty-six (28%) operations were considered as emergency procedure. Twenty-four (15%) procedures were reoperations. RESULTS: Mean ASCP time was 48+/-20 min. Hospital mortality was 8.6% (n=14; 70% confidence limit (CL): 6.4-10.8%). Univariate risk factors for hospital mortality were acute type A dissection (P=0.003), central neurologic damage <24 h before the operation (P=0.000), preoperative hemodynamic instability (P=0.034), and rethoracotomy for any cause (P=0.036). Logistic regression analysis identified central neurologic damage <24 h (P=0.006, odds ratio 14) as an independent risk factor. Temporary neurologic damage occurred in 3.8% (n=6; 70% CL: 2.3-5.3%) of patients. Logistic regression analysis indicated preoperative hemodynamic instability (P=0.003, odds ratio 13) as an independent risk factor. Perioperative permanent central neurologic damage was reported in another 3.8% (n=6; 70% CL: 2.3-5.3%) patients. Acute type A dissection (P=0.018, odds ratio 8) and the non-use of a midline sternotomy (P=0.049, odds ratio 8) were retained as independent risk factors. CONCLUSION: Hospital mortality and perioperative neurologic complications are not significantly influenced by the duration of antegrade selective cerebral perfusion. Overall complication rate is low.

Adult↗
PubMed2000

The effect of two low-dose propofol infusions on the relationship between six-pulse transcranial electrical stimulation and the evoked lower extremity muscle response.

BACKGROUND: Transcranial stimulation of the motor cortex using high-voltage electrical stimuli given in train is a method of monitoring the integrity of the motor pathways during thoracoabdominal aortic aneurysm surgery. The purpose of this study was to assess the relationship between the stimulus intensity and the corresponding amplitude of the myogenic motor evoked potential (tcMEP) in response to six-pulse transcranial electrical stimulation during two levels of low-dose propofol infusion and stable fentanyl/nitrous oxide anaesthesia. METHODS: Nine patients (37-78 yr) scheduled to undergo surgery on the thoracoabdominal aorta were studied. After achieving a stable anaesthetic state the output voltage was decreased with 50 V intervals from 350 V to 200 V during a target propofol infusion aimed at a plasma steady-state concentration of 0.7 microg x ml(-1) and increased with 50 V intervals from 200 V to 450 V during a target propofol infusion aimed at a plasma steady-state concentration of 1.4 microg x ml(-1). TcMEPs were recorded from the right tibialis anterior muscle. RESULTS: Doubling the target propofol infusion to 1.4 microg x ml(-1) resulted in a 30-50% decrease in tcMEP amplitude. The largest tcMEP amplitude using the six-pulse paradigm was found during a propofol infusion aimed at a plasma concentration of 0.7 microg x ml(-1) and demanded a stimulus output of 350 V, corresponding to a charge density of 7.5 microC x cm(-2) per phase. CONCLUSION: Doubling the target propofol infusion to 1.4 microg x ml(-1) provides less robust, but still recordable tcMEPs in response to six-pulse electrical stimulation. Safety guidelines are discussed.

Adjuvants, Anesthesia↗
PubMed1999

[Bilateral blood pressure measurement before and after coronary bypass surgery: an absolute necessity].

Anginous symptoms and a difference in blood pressure between the two arms prompted angiography in two patients, men aged 66 and 50 years. The examination revealed coronary sclerosis and a stenosis in the left subclavian artery. The symptoms disappeared after percutaneous dilatation of the subclavian artery, followed by a coronary bypass operation (CABG) using an internal thoracic artery (a branch of the subclavian artery). In two other patients, men aged 61 and 71 years, who had undergone an arterial CABG 12 years previously, anginous symptoms were the manifestation of a narrowed subclavian artery. The symptoms disappeared after balloon dilatation of the subclavian artery and revascularization of the anterior interventricular branch (left artery descendens) and embolization of the internal thoracic artery graft (internal mammarian artery graft), respectively. Stenosis or occlusion of the proximal subclavian artery may attenuate the blood flow in the ipsilateral A. thoracica interna graft. The diagnosis can simply be made by bilateral blood pressure measurement.

Angina Pectoris↗
PubMed1999

A 23-year experience with composite valve graft replacement of the aortic root.

BACKGROUND: This is a retrospective study of early and long-term results of composite valve graft replacement of the aortic root. METHODS AND RESULTS: Between July 1974 and July 1997, 244 patients underwent aortic root replacement with a composite valve graft. Mean age was 54+/-15 years. The inclusion technique was used in 178 patients (73.0%), the open technique in 65 (26.5%), and the Cabrol II technique in 1 patient (0.5%). Hospital mortality was 7.8% (70% confidence limit, 6.1% to 9.5%). Independent determinants of hospital mortality were preoperative creatinine level more than 150 micromol/L (p = 0.04), prolonged cardiopulmonary bypass time (p = 0.006), intraoperative technical problems (p = 0.048), and year of operation (p = 0.015). Follow-up was 99.6% complete, median 96 months (range, 2 to 256 months). Fifty-seven patients (25.3%; 70% confidence limit, 22.4% to 28.2%) died during follow-up. Cumulative survival at 5, 10, and 20 years was 76%, 62%, and 33%. Independent risk factors for late death were postoperative complications (p = 0.027), technique for coronary reattachment (p = 0.028), and concomitant aortic arch operation (p = 0.01). Twenty patients (8.8%; 70% confidence limit, 7.0% to 10.6%) underwent reoperation on the aortic root. Estimated freedom from reoperation for pseudoaneurysms at 3 years was 96% in the inclusion group and 94% in the open group (p = 0.236). CONCLUSIONS: Aortic root replacement with a composite valve graft can be performed with low hospital mortality and morbidity. Pseudoaneurysms did occur in the inclusion group, but also in the open group.

Adolescent↗
PubMed1999

Cryopreserved aortic allografts for aortic root reconstruction: a single institution's experience.

BACKGROUND: An evaluation of early and long-term results of aortic root replacement with cryopreserved aortic allografts and echocardiographic follow-up of allograft valve function was performed. METHODS: From September 1989 through May 1998, 132 patients aged 17 to 77 years (mean, 50.8 +/- 14.8 years) underwent freestanding aortic root replacement with a cryopreserved aortic allograft. Eighty-six (65.1%) patients had New York Heart Association class III or IV functional status before operation, and 27 (20.5%) patients underwent emergency operation. Fifty-nine (44.7%) patients had undergone previous cardiac operations. The cause of aortic disease was acute endocarditis in 63 (47.7%) patients, healed endocarditis in 15 (11.3%), degenerative in 20 (15.2%), congenital in 20 (15.2%), failed prosthesis in 10 (7.6%) and rheumatic in 4 (3.0%). Follow-up was complete, with a mean of 42 months. RESULTS: There were 12 hospital deaths (9.1%; 70% confidence limits [CL], 6.6% and 11.6%); 9 of them were operated on for active endocarditis (p = 0.062). Multivariate analysis determined age older than 65 years (p = 0.012) and emergency operation (p = 0.009) as independent risk factors for hospital mortality. During follow-up, 6 (5.0%; 70% CL, 3.0% and 7.0%) patients died. Cumulative survival rate for the entire group was 81.8% +/- 5.4% at 8 years. Freedom from reoperation for structural valve failure was 100%, freedom from reoperation for any cause was 96.3% +/- 1.8% at 8 years. Freedom from endocarditis at 8 years was 97.9% +/- 1.4%. Follow-up of allograft valve function showed no or trivial aortic regurgitation in 97% of patients and absence of stenosis of the allograft in 100%. CONCLUSIONS: Aortic root replacement with cryopreserved aortic allografts can be performed with acceptable hospital mortality and long-term results. The durability of cryopreserved aortic allografts is good, and reoperation for structural valve failure is absent at 8 years.

Adolescent↗
PubMed1999

Impact of left heart bypass on the results of thoracoabdominal aortic aneurysm repair.

BACKGROUND: This study evaluated the role of left heart bypass on the results of thoracoabdominal aortic aneurysm (TAAA) operations. METHODS: Two hundred fifty-eight patients had surgical repair of a thoracoabdominal aortic aneurysm between 1981 and 1998 using the inlay technique. Simple cross-clamping was used in 47.7% and left heart bypass (atriodistal) in 52.3%. Further surgical technique was identical: liberal intercostal or lumbar artery reimplantation, cerebrospinal fluid drainage (since 1989), administration of a renal cooling solution, permissive mild hypothermia, and no pharmacologic protection. Both univariate and multivariate analysis were used. RESULTS: The hospital mortality rate was 10.1% overall: 14.6% in the cross-clamp group, and 5.9% in the bypass group (p = 0.02). The risk of hospital death increased with aneurysm rupture (odds ratio 5.6) and when the patient needed postoperative dialysis (odds ratio 7.5). The use of left heart bypass had a mild protective effect on hospital death (odds ratio 0.56). The incidence of postoperative renal failure requiring dialysis was 8.3% overall: 10.9% in the cross-clamp group, and 5.9% in the bypass group (p = 0.16). After multivariate analysis, a longer operative procedure (odds ratio 1.01 per minute) and a longer reappearance time of blue dye in the urine (odds ratio 1.05 per minute) increased the risk of dialysis, whereas the use of atriodistal bypass reduced that risk (odds ratio 0.08). Paraplegia or paraparesis occurred in 10.9% of patients overall: 13.2% in the cross-clamp group, and 8.8% in the bypass group (p = 0.27). After logistic regression, rupture increased the risk of paraplegia or paraparesis (odds ratio 3.2) and dissection reduced it (odds ratio 0.23). CONCLUSIONS: The use of atriodistal bypass is beneficial in patients who had thoracoabdominal aortic aneurysm repair. Hospital mortality rates, postoperative dialysis, and paraplegia/paraparesis were reduced.

Adult↗