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Bas Mochtar

Publications and source records attributed to Bas Mochtar.

8 recordsLinked to original sources
PubMed2006

The value of motor evoked potentials in reducing paraplegia during thoracoabdominal aneurysm repair.

OBJECTIVE: Paraplegia after thoracoabdominal aortic aneurysm (TAAA) repair mainly occurs in patients with Crawford extent I and II. We assessed the impact of monitoring spinal cord integrity and the subsequent adjusted surgical maneuvers on neurologic outcome in repairs of type I and II TAAAs. METHODS: Surgical repair of TAAAs was performed in 112 consecutive patients with extent type I (n = 42) and type II (n = 70) aneurysms. The surgical protocol included cerebrospinal fluid drainage, moderate hypothermia, and left heart bypass with selective organ perfusion. Spinal cord function was assessed by means of monitoring motor evoked potentials (MEPs). Significant decreased MEPs always generated adjustments, including raising distal aortic and mean arterial pressure, reattachment of visible intercostal arteries, or endarterectomy of the excluded aortic segment with revascularization of back bleeding intercostal arteries. RESULTS: Motor evoked potential monitoring could be achieved in all patients. By maintaining a mean distal aortic pressure of 60 mm Hg, MEPs were adequate in 82% of patients. Increasing distal aortic pressure restored MEPs in all patients. In 19 patients (17%), MEPs decreased significantly during aortic cross-clamping because of critical spinal cord ischemia. MEPs returned in all patients after spinal cord blood flow was re-established except in three patients with type II TAAA in whom MEPs could not be restored, and absent MEPs at the end of the procedure corresponded with neurologic deficit. Delayed paraplegia developed in two patients owing to hemodynamic instability with insufficient mean arterial blood pressure to maintain adequate spinal cord perfusion. CONCLUSION: Monitoring MEPs is a highly reliable technique to assess spinal cord ischemia during TAAA repair. A surgical protocol including cerebrospinal fluid drainage, left heart bypass, and monitoring of MEPs can reduce the paraplegia rate significantly. Adjusted hemodynamic and surgical strategies induced by changes in MEPs could restore spinal cord ischemia in most patients, preventing early and late paraplegia in all type I patients. In type II patients, early paraplegia occurred in 4.2% and delayed neurologic deficit in 2.9%. Despite all available measures, complete prevention of paraplegia in type II aneurysms seems to be unrealistic.

Adult↗
PubMed2004

Prevention of renal failure in patients undergoing thoracoabdominal aortic aneurysm repair.

OBJECTIVE: Renal failure is a potential complication after thoracoabdominal aortic aneurysm (TAAA) repair and is a significant risk factor for postoperative mortality. We assessed the results of distal aortic perfusion and continuous volume-controlled and pressure-controlled blood perfusion of the kidneys during TAAA repair in patients with preoperative normal and impaired renal function. METHODS: Surgical repair of TAAA was performed in 279 consecutive patients (type I, n = 90; type II, 117; type III, 42; type IV, 30). In 195 patients preoperative renal function was normal; however, in 84 patients renal insufficiency was diagnosed (serum creatinine concentration [SCr], 1.4-2.0 mg/dL, n = 46; SCr, 2.0-2.5 mg/dL, n = 20; and SCr, >2.5 mg/dL, n = 18). Renal perfusion was established with catheters connected to the left-sided heart bypass. Volume flow was assessed with ultrasound, and pressure channels in the catheters enabled pressure- controlled perfusion of the kidneys. RESULTS: Selective renal artery perfusion was achieved in all patients without technical problems or complications. In each catheter, mean arterial pressure was 69 mm Hg and volume flow was 275 mL/min. During aortic cross-clamping, urine output was uninterrupted, irrespective of clamp time. Most patients demonstrated limited or moderate increase in SCr concentration. In 17 patients (6%) SCr doubled, and peaked above 3 mg/dL, but returned to baseline levels within several days. Three patients (1%) required temporary dialysis but were discharged without further need for dialysis. In general, preoperative renal impairment did not worsen. CONCLUSION: Distal aortic and selective renal blood perfusion is an effective measure to protect renal function during TAAA repair, but only if perfusion is provided with adequate volume and pressure. This technique also averts dialysis in most patients with preoperative renal failure.

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PubMed2003

Pressure-volume loops in patients with aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Preoperative left ventricular (LV) function is the strongest predictor of outcome after valve replacement for aortic stenosis (AS). Although pressure-volume analysis with the conductance catheter technique can provide detailed information on LV systolic and diastolic function, this technique has not yet been used in AS patients. The present study examined the potential use of LV function measurements using pressure-volume analysis with a conductance catheter during surgery for AS. METHODS: In six patients with severe symptomatic AS, a conductance catheter was placed under transesophageal echocardiographic guidance in the left ventricle via the right superior pulmonary vein. RESULTS: The procedure was successful in all patients and lengthened the duration of surgery by <30 min, but with no increase in bypass or aortic cross-clamp times. Pressure-volume analysis showed that systolic function was normal in all patients (ejection fraction 42-59%, end-systolic elastance 1.6-4.5 mmHg/ml), while diastolic dysfunction was found in all patients (Tau 32-96 ms, LV end-diastolic pressure 7-42 mmHg, atrial kick 25-60%). After valve replacement, systolic function improved, but diastolic function did not. CONCLUSION: The conductance catheter placed via the pulmonary vein can determine LV systolic and diastolic dysfunction in detail in an individual patient with AS before and after valve replacement. The technique may be used to extend diagnostic data from less-invasive modalities and to determine prognosis in the individual patient.

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PubMed2002

Beating-heart surgical treatment of atrial fibrillation with microwave ablation.

BACKGROUND: In this feasibility study, early results are presented of our first series of patients with microwave ablation for atrial fibrillation (AF) on the beating heart. METHODS: From June 2001 until December 2001, a total of 24 patients underwent beating-heart epicardial ablation for AF. With a microwave antenna, the left and right pulmonary veins were isolated and connected to each other followed by amputation of the left atrial appendage. Subsequently, patients underwent either off-pump coronary artery bypass graft or valve surgery on pump. The mean age of the patients was 67.4 +/- 6 years. Three patients experienced paroxysmal atrial fibrillation and all others chronic AF. Mean left atrial diameter was 5.4 +/- 0.6 cm, and mean ablation time was 13 min. RESULTS: All procedures but one were completed successfully on the beating heart. All patients were in sinus rhythm after the procedure. A total of 15 patients experienced periods with postoperative AF during hospital stay; 9 of these patients were discharged with AF. All patients received either sotalol or amiodarone. At latest follow-up (3 to 9 months), 20 of 23 patients were in sinus rhythm. CONCLUSIONS: With microwave ablation, electrical isolation of the pulmonary veins can be achieved epicardially without cardiopulmonary bypass support.

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PubMed2002

Assessment of spinal cord integrity during thoracoabdominal aortic aneurysm repair.

BACKGROUND: Monitoring motor-evoked potentials (MEPs) is an accurate technique to assess spinal cord integrity during thoracoabdominal aortic aneurysm (TAAA) repair, guiding surgical strategies to prevent paraplegia. METHODS: In 210 consecutive patients with type I (n = 75), type II (n = 103), and type III (n = 32) TAAA surgical repair was performed using left heart bypass, cerebrospinal fluid drainage, and MEPs monitoring. RESULTS: Reliable MEPs were registered in all patients. The median total number of patent intercostal and lumbar arteries was five. After proximal aortic crossclamping, MEP decreased below 25% of base line in 72 patients (34%) indicating critical spinal cord ischemia, which could be corrected by increasing distal aortic pressure. By using sequential clamping it appeared that in 43% of type I and II cases spinal cord circulation was supplied between T5 and L1, and 57% between L1 and L5. In type II and III cases cord perfusion was dependent upon lower lumbar arteries in 16% and pelvic circulation in 8%, necessitating reattachment of these segmental arteries. In 9% of patients critical ischemic MEP changes occurred without visible arteries, requiring aortic endarterectomy and selective grafting. One patient suffered early paraplegia and 2 delayed, and 2 patients had temporary neurologic deficit (5 of 210; 2.4%). CONCLUSIONS: In patients with TAAA, blood supply to the spinal cord depends upon a highly variable collateral system. Monitoring MEPs is an accurate technique for detecting cord ischemia, guiding surgical tactics to reduce neurologic deficit (2.4%).

Adult↗
PubMed2002

Spinal cord blood supply in patients with thoracoabdominal aortic aneurysms.

OBJECTIVE: In patients with thoracoabdominal aortic aneurysms (TAAAs), the blood supply to the spinal cord is highly variable and unpredictable because of obstructed intercostal and lumbar arteries. This study was performed for the prospective documentation of patent segmental arteries during TAAA repair and the assessment of their functional contribution to the spinal cord blood supply. METHODS: TAAA repair was performed in 184 consecutive patients (68 with type I aneurysm, 91 with type II, and 25 with type III) according to a protocol that included left heart bypass grafting, cerebrospinal fluid drainage, and the monitoring of motor-evoked potentials (MEPs). Patent intercostal and lumbar arteries were documented, and all reattached, selectively grafted, and oversewn segmental arteries were noted. MEP amplitude that decreased to less than 25% of baseline was considered an indication of critical spinal cord ischemia and prompted spinal cord revascularization. RESULTS: Adequate MEP levels were encountered in 183 of 184 patients. One patient had early paraplegia (absent MEPs), two patients had delayed paraplegia develop, and two patients had temporary paraparesis, which accounted for an overall neurologic deficit of 2.7%. The median total number of patent intercostal and lumbar arteries in type I, II, and III aneurysms was three, five, and five, respectively. In eight of 68 type I cases, no segmental arteries were seen between the fifth thoracic vertebrae (T5) and the first lumbar vertebrae (L1) and MEP levels remained adequate because of distal aortic perfusion. In 18 of 91 type II cases, the aortic segment T5 to L1 did not contain patent arteries, and in six of these patients, the segment L1 to L5 did not have lumbar arteries either. In the latter patients, MEP levels depended on the pelvic circulation provided with the left heart bypass graft. In the other 12 of 91 type II cases, the only patent arteries were the lumbar arteries between L3 and L5. The loss of MEPs could be corrected with the reattachment of these arteries. In seven of 25 type III cases, the MEP levels also depended on lumbar arteries L3 to L5 and in three of 25 cases, no segmental arteries were available and MEP levels recovered after the reperfusion of the pelvic circulation. With the combination of the findings of type II and III cases, spinal cord perfusion was directed by lower lumbar arteries in 16% of the cases (19 of 116) and pelvic circulation in 8% of the cases (nine of 116). CONCLUSION: In patients with TAAA, most intercostal and lumbar arteries are occluded and spinal cord perfusion depends on an eminent collateral network, which includes lumbar arteries and pelvic circulation. The monitoring of MEPs is a sensitive technique for the assessment of spinal cord ischemia and the identification of segmental arteries that critically contribute to spinal cord perfusion. Surgical strategies on the basis of this technique reduced the incidence rate of neurologic deficit to less than 3%.

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