Robert Ritchie Linton.
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Biomedical subjects
Publications and source records attributed to T F Dodson.
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This study measured cardiac output before and 1 or 2 yr after orthotopic liver transplantation in 23 patients. Cardiac output was measured by thermodilution before transplantation and by first-pass radionuclide angiocardiography at follow-up. Study patients were selected as those doing well clinically and by standard laboratory tests at 1-yr and 2-yr reevaluations with no evidence of rejection: six had mild recurrent hepatitis shown on biopsy samples. Hepatocyte function was normal at the time of the study as shown by galactose elimination capacity of 442 +/- 90 mg/min. Medications were cyclosporine and prednisone in all patients, azathioprine in 10 patients and a combination of antihypertensive therapy to maintain diastolic blood pressure less than 90 mm Hg in 20 patients. Mean (+/- S.D.) pretransplantation cardiac output was 9.1 +/- 3.1 L/min and remained elevated at 8.3 +/- 2.1 L/min 1 yr, and 9.6 +/- 2.6 L/min (n = 13) 2 yr after transplantation. A significant (p less than 0.001) correlation was found between pretransplant and follow-up cardiac output. End diastolic, end systolic and stroke volumes are all increased in a pattern similar to that seen in end-stage cirrhosis. These data show that the high cardiac output of the hyperdynamic state of advanced liver disease persists after liver transplantation. The mechanisms and consequences of this require further study.
Liver blood flow and systemic hemodynamics were measured intraoperatively in 34 patients after liver transplantation. Ultrasound transit-time flow probes measured hepatic arterial and portal venous flow over 10 to 75 min 1 to 3 hr after reperfusion. Cardiac output was measured by thermodilution. Mean cardiac output was 9.5 +/- 2.8 L/min; the mean total liver blood flow of 2,091 +/- 932 ml/min was 23% +/- 11% of cardiac output. Mean portal flow of 1,808 +/- 929 ml/min was disproportionately high at 85% +/- 10% of total liver blood flow. Correlation analysis showed a significant (p less than 0.01; r = 0.42) correlation between cardiac output and portal venous flow and a trend toward negative correlation (p = 0.087) between cardiac output and hepatic arterial flow. These data show that increased flow in the newly transplanted liver is predominantly portal venous flow and is associated with high cardiac output and reduced hepatic arterial flow. In the last 13 patients studied, portal flow was reduced by 50% and the hepatic artery response was measured. We saw a significant (p less than 0.05) increase in hepatic artery flow from 322 +/- 228 to 419 +/- 271 ml/min, indicating an intact hepatic arterial buffer response. The hepatic artery response also showed that it is a reversible rather than a fixed resistance that contributes to the low hepatic artery flow in these patients.
This study reports the Emory experience with 147 distal splenorenal shunts (DSRS) and 110 orthotopic liver transplants (OLT) between January 1987 and December 1991. The purpose was to clarify which patients with variceal bleeding should be treated by DSRS versus OLT. Distal splenorenal shunts were selected for patients with adequate or good liver function. Orthotopic liver transplant was offered to patients with end-stage liver disease who fulfilled other selection criteria. The DSRS group comprised 71 Child's A, 70 Child's B, and 6 Child's C patients. The mean galactose elimination capacity for all DSRS patients was 330 +/- 98 mg/minute, which was significantly (p less than 0.01) above the galactose elimination capacity of 237 +/- 82 mg/minute in the OLT group. Survival analysis for the DSRS group showed 91% 1-year and 77% 3-year survival, which was better than the 74% 1-year and 60% 3-year survivals in the OLT group. Variceal bleeding as a major component of end-stage disease leading to OLT had significantly (p less than 0.05) poorer survival (50%) at 1 year compared with patients without variceal bleeding (80%). Hepatic function was maintained after DSRS, as measured by serum albumin and prothrombin time, but galactose elimination capacity decreased significantly (p less than 0.05) to 298 +/- 97 mg/minute. Quality of life, measured by a self-assessment questionnaire, was not significantly different in the DSRS and OLT groups. Hospital charges were significantly higher for OLT (median, $113,733) compared with DSRS ($32,674). These data support a role for selective shunt in the management of patients with variceal bleeding who require surgery and have good hepatic function. Transplantation should be reserved for patients with end-stage liver disease. A thorough evaluation, including tests of liver function, help in selection of the most appropriate therapeutic approach.
The case records of all infants under the age of 6 months who underwent surgery for acute arterial thrombosis between January 1980 and September 1991 were reviewed. Seven infants (nine ischemic limbs) were identified and ranged in age from 5 days to 5 1/2 months (mean 2.4 months); all weighed less than 5 kg (mean 3.9 kg). The cause in each case was iatrogenic. Diagnosis was based on the presence of a cool, mottled extremity associated with the absence of insonated peripheral arterial Doppler signals. Treatment included aortoiliac thrombectomy (n = 2), femoral artery thrombectomy with primary closure (n = 4), femoral artery thrombectomy with autogenous saphenous vein patch (n = 1), and axillary artery thrombectomy with end-to-end anastomosis (n = 1). Palpable pulses were restored in five (56%) of nine limbs and Doppler signals in the remaining limbs. There were no instances of limb loss. Excluding aortoiliac thrombectomy, palpable peripheral pulses were reestablished in only 40% of extremities. Thrombectomy is a safe and simple procedure in even the very youngest of patients with arterial insufficiency, but surgical optimism should be tempered by frequent inability to achieve full and durable success.
The intra-aortic balloon pump (IABP) has been used for 23 years to treat cardiogenic shock from various causes. A retrospective review was conducted to evaluate the morbidity, mortality, and risk factors associated with insertion of this device. Over a recent 3-year period, 415 such pumps were inserted either by percutaneous (323) or cut-down (92) technique in 404 patients. Indications for placement included intraoperative pump failure (46%), cardiac instability before coronary artery bypass grafting (28%), perioperative support (13%), cardiac transplantation (7%), and cardiogenic shock (6%). Noncardiac vascular complications occurred in 67 patients, 55 per cent of whom required surgical correction. Operative procedures included femoral artery thrombectomy, bypass grafting, fasciotomy, and amputation. Major risk factors for vascular complications included diminished or absent femoral pulses on initial examination, being a woman, and obesity. In patients with known peripheral vascular disease, the risk of a vascular complication was 17.9 per cent when a surgical cut-down technique was used to insert the IABP, and 38.9 per cent when a percutaneous insertion was performed. The mortality doubled in those patients who had a vascular complication as compared to those who did not (34% vs 17%). A more liberal use of an open surgical technique in those patients with peripheral vascular disease, obesity, and who are women may help to reduce complications after the insertion of the intra-aortic balloon pump.
Renal cell carcinoma extends into the lumen of the inferior vena cava in approximately 4% of patients at the time of diagnosis. Surgical removal of the intracaval tumor thrombus with radical nephrectomy is the preferred treatment for this malignancy. From January 1977 to June 1990, 31 such patients were examined for combined problems of renal carcinoma and intracaval tumor extension. Twenty-six of these patients underwent radical nephrectomy and vena caval thrombectomy. Ten patients had tumor thrombus confined to the infrahepatic vena cava, 11 had retrohepatic caval involvement, and 5 had extension to the level of the diaphragm or into the right atrium. Surgical approach was dictated by the level of caval involvement. Control of the suprahepatic vena cava plus temporary occlusion of hepatic arterial and portal venous inflow were necessary in some cases; cardiopulmonary bypass was required for transatrial removal of more extensive tumors. Five of the 26 patients had evidence before operation of distant metastatic disease; none of these survived beyond 12 months. The 5-year actuarial survival rate of the 21 patients without known preoperative metastatic disease was 57%. Complete surgical excision of all gross tumor appears to be critical for long-term survival in these patients.
Bleeding from gastroesophageal varices remains the most devastating complication of the portal hypertensive syndrome. Endoscopic sclerotherapy has emerged as the best initial treatment for bleeding varices because surgery is obviated and survival may be improved. However, sclerotherapy will fail and surgical rescue will be required in at least a third of patients. There are two viable surgical rescue procedures: shunt surgery and liver transplantation. This paper summarizes the available data and concludes that there is a role for both procedures.
Orthotopic liver transplantation (OLT) has become standard therapy for patients with acute hepatic necrosis and end-stage liver disease. This study measured change in hepatic function (galactose elimination capacity [GEC]), liver blood flow (low dose galactose clearance: flow), hepatic volume (CT scan; volume) and morphology after OLT. The aim was to measure the physiologic response after OLT and compare this response with that after selective shunt (SS) and sclerotherapy (ES) to determine which patients should receive specific therapy. Between January 1987 and November 1988, 37 patients underwent OLT. Operative mortality was 18%, which was similar to that of SS in Child's C cirrhotics. GEC and volume were less in transplant patients than in cirrhotics treated with SS or ES. GEC, flow, and volume normalized after OLT; GEC was preserved after ES and SS, but volume decreased. Three preoperative patterns were observed that can aid in selection of OLT candidates. Patients with chronic cirrhosis (chronic active hepatitis; cryptogenic) need OLT when GEC is less than or equal to 225 mg/min and volume is less than or equal to 50% normal. Patients with Budd-Chiari Syndrome require OLT if cirrhosis has evolved. Patients with sclerosing cholangitis and primary biliary cirrhosis qualify for transplants when complications of the portal hypertensive syndrome develop. The studies can also direct therapy for ES failures. Selective shunt is indicated in those patients with stable disease whose GEC is greater than or equal to 300 mg/min and liver volume is greater than 75% normal; OLT is indicated for cirrhotics with GEC that is less than 225 mg/min and liver volume that is less than 50% predicted normal.
A new method of arterial grafting during orthotopic hepatic transplantations is described herein. The advantages compared with other techniques include better exposure, less extensive dissection, reduced blood loss and, with correct anatomic orientation, a reduced risk of kinking the graft in a blind tunnel.
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