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Biomedical subjects

J T Christenson

Publications and source records attributed to J T Christenson.

At least 19 recordsLinked to original sources
PubMed2002

Aortic arch replacement using a four-branched aortic arch graft.

Surgical repair for aortic arch aneurysms is associated with considerable mortality and morbidity. Adequate brain protection is essential. Experience of aortic arch repair in six patients using a four-branched arch graft is described. There were two emergency and three reoperations. One patient had ruptured aneurysm. Hypothermic cardiopulmonary bypass (18-22 degrees C) was employed. A four-branched polymer albumin-coated arch graft was used. The fourth branch of the graft was used for secondary arterial cannulation to ensure continuous brain circulation. One hospital death occurred. No permanent neurological event occurred. The four-branched arch graft facilitates fashioning arch branch anastomoses and provides better brain protection.

Aged↗
PubMed2001

Preoperative lipid control with simvastatin reduces the risk for graft failure already 1 year after myocardial revascularization.

Hypercholesterolemia is a recognized risk factor for development of atherosclerosis in both native coronary arteries and bypass grafts. Lipid-lowering therapy with statins is effective. Few data are available for studies on bypass grafts. The influence of hypercholesterolemia on development of bypass graft disease was studied. Clinical and angiographic follow up 1yr after CABG of patients with a preoperative cholesterol >6.2mmol/l, with a preoperative lipid control (group 2) or controls (group 1) and patients with cholesterol <4.7mmol/l (group 3) were studied. Patient demographics, angiography and operation data were the same in all the groups. Group 1 patients had significantly higher incidence of graft lesions, requiring more interventions than Group 2. Sequential vein bypass grafts showed superior features compared to single vein grafts. Preoperative lipid control with statins is strongly recommended, since uncontrolled hypercholesterolemia has a direct impact on the outcome of CABG procedure. It significantly reduces the development of vein graft obstructive disease.

Female↗
PubMed2001

Effective surgical management of high-risk coronary patients using preoperative intra-aortic balloon counterpulsation therapy.

The proportion of high-risk coronary patients submitted to surgical myocardial revascularization (CABG) is steadily increasing. High-risk patients utilize more hospital resources and have a higher procedural cost than low-moderate risk CABG patients. An efficient management is essential to improve outcome and reduce costs. This report entails three study periods. In an initial retrospective study coronary high-risk criteria were established. At least two of the following factors were required: redo CABG, unstable angina, left main stem stenosis greater than 70%, preoperative left ventricular ejection fraction < 0.30 and diffuse coronary artery disease. Poor preoperative cardiac performance was the major contributing factor for poor outcome. Intra-aortic balloon counterpulsation therapy (IABP) was introduced as preoperative therapy. During a second study period prospective randomized studies found preoperative IABP-therapy efficient, significantly improving both preoperative cardiac index (P < 0.0001), decreasing postoperative mortality (P < 0.0001) and morbidity, shorten intensive care unit stay as well as total hospital stay (P < 0.0001). Drug consumption was significantly reduced (P < 0.0001). Optimal timing was found to be 2 h prior to aortic cross-clamping and the therapy was found highly cost-beneficial with an average 36% reduction of the total procedural cost. During a third study period, well beyond any study protocol period, preoperative IABP therapy was again found highly effective with a close to 100% utilization rate in high-risk patients and continuous efficacy with excellent outcome, despite acceptance of sicker patients. During this post-study evaluation period 1/3 of the high-risk patients presented with 4 of the established risk factors. The use of preoperative IABP therapy is therefore highly recommended for high-risk coronary patients undergoing CABG.

Adult↗
PubMed2001

Obtaining a superficial femoral artery graft in adolescents and children with the deep femoral artery transposition.

A new technique to obtain a segment of the superficial femoral artery as an arterial conduit in young patients while an unobstructed peripheral blood flow is maintained by superficial femoral artery-deep femoral artery transposition is illustrated with two clinical examples. The explanted arterial autograft requires no replacement by another graft and provides a conduit of up to 10 cm in length. Excellent results were achieved in both patients at 1 year. This technique is recommended instead of saphenous vein conduits in very young patients because of the risk for late vein degeneration.

Adolescent↗
PubMed2001

Impact of double internal thoracic artery grafts on long-term outcomes in coronary artery bypass grafting.

We performed this study to determine if bilateral internal thoracic artery grafts provide greater benefit than single internal thoracic artery grafts. Six hundred ninety-four consecutive patients who received 2 coronary grafts in a single operation during 1983-1989 were given 10 years of follow-up and then analyzed retrospectively. Group 1 (n=382) received 2 internal thoracic artery grafts, Group 2 (n= 139) received 1 internal thoracic artery graft and 1 saphenous vein graft, and Group 3 (n= 173) received 2 saphenous vein grafts. Patient demographics, preoperative angiographic findings, and operative indications were the same. Hospital mortality rates were 2.6%, 2.2%, and 2.3%, respectively. Hemorrhage, sternal wound infection, mediastinitis, sternal dehiscence, and prolonged ventilatory support showed no group differences. Follow-up over 10 years was complete in 677 survivors. Mortality rates during follow-up were 1.8%, 2.9%, and 4.7%, respectively. Cardiac-related mortality rates were 71%, 75%, and 88%, respectively (Group 1 vs Group 3, P=0.0412). Ten-year survival was better for Group 1 than for Groups 2 and 3 (P=0.0356 and P <0.0001). Cardiac-event-free survival at 10 years was 93% in Group 1, 84% in Group 2, and 74% in Group 3 (all P <0.0001). The use of 2 internal thoracic artery grafts resulted in significantly lower risk of cardiac death and re-intervention, compared with the use of 1 internal thoracic artery, which in turn was superior to the use of vein grafts. Use of double internal thoracic arteries did not increase postoperative complications.

Adult↗
PubMed2001

Pre-operative intra-aortic balloon counterpulsation in stable patients with left main coronary disease.

OBJECTIVE: To determine whether prophylactic, pre-operative, intra-aortic balloon counterpulsation (IABC) improves clinical outcome in stable patients with severe left main coronary artery disease. METHODS: A post-hoc analysis of 457 prospectively tracked, non-randomized patients undergoing coronary artery bypass graft surgery (CABG) for left main stenoses 50% and multivessel coronary disease, but without any hemodynamic compromise or ongoing angina, was conducted. Patients with heart failure, shock, ongoing ischemia or previous CABG were excluded. In 287 patients, pre-operative IABC was not used (Group 1), while IABC was initiated in 170 patients for "prophylaxis" (Group 2). RESULTS: Groups 1 and 2 were similar in age (67 +/- 10 years versus 67 +/- 11 years, respectively), sex (72% male versus 71% male, respectively), and body mass index (28 +/- 5.5 versus 27 +/- 5.1, respectively). However, more Group 1 patients had peripheral vascular disease (PVD) (25% versus 11%), but more Group 2 patients had diabetes (37% versus 29%), and a lower left ventricular ejection fraction. The unadjusted 30-day mortality was significantly higher in Group 1 [16 (5.6%) versus 2 (1.2%); p = 0.02]. Cardiopulmonary bypass time and post-operative length of stay did not differ between the two groups. After adjusting for PVD in the multivariate analysis, the p-value for the no IABP versus IABP comparison in the presence of PVD was 0.10, even though 0/18 patients with PVD and IABC died. CONCLUSION: While unadjusted mortality appears lower with prophylactic IABC, confounding variables such as PVD mandate a larger, randomized clinical trial in order to establish the role of IABC in stable patients with left main disease.

Age Factors↗
PubMed2000

Economic impact of preoperative intraaortic balloon pump therapy in high-risk coronary patients.

BACKGROUND: The efficacy of preoperative intraaortic balloon pump therapy in high-risk coronary patients has been demonstrated earlier. METHODS: This study investigates the economic aspect by a detailed cost analysis of pooled information from two previously published randomized studies and 144 consecutive low-risk coronary artery bypass graft operations. Costs for patients receiving preoperative intraaortic balloon pump therapy before aortic cross-clamping (n = 62) were compared to those in a control group (n = 50). Detailed cost analysis was based on data provided by the hospital finance department. RESULTS: The total hospital costs were as follows: low-risk coronary artery bypass graft operations cost 35,335+/-1,694 Swiss francs ($23,400+/-$1,121); high-risk coronary artery bypass graft without preoperative intraaortic balloon pump therapy cost 65,892+/-31,719 Swiss francs ($43,637+/-$21,006); and high risk coronary artery bypass graft with preoperative intraaortic balloon pump therapy cost 41,948+/-10,379 Swiss francs ($27,780+/-$6,874) (p = 0.0015). There were no significant differences in average cost among the preoperative intraaortic balloon pump therapy subgroups. CONCLUSIONS: Preoperative intraaortic balloon pump therapy in high risk coronary patients is significantly cost-beneficial, With an average saving of 24,000 Swiss francs ($16,000) on the total hospital cost, a 36% cost reduction.

Cardiac Output, Low↗
PubMed2000

Endovascular repair using vein-covered stents in the carotid artery bifurcation.

The treatment of a bleeding carotid artery pseudoaneurysm in a patient using endovascular repair is described. Vein-covered stents were successfully employed. There were no neurological complications and no recurrent bleeding during 8 months follow up and carotid artery continuity was achieved. Stents covered with saphenous vein may be considered a treatment option for endovascular repair of pseudoaneurysm of the carotid artery.

Aneurysm, False↗
PubMed2000

Should a regurgitant mitral valve be replaced simulataneously with a stenotic aortic valve?

Mitral valve regurgitation frequently accompanies aortic valve stenosis. It has been suggested that mitral regurgitation improves after aortic valve replacement alone and that the mitral valve need not be replaced simultaneously Furthermore, mitral regurgitation associated with coronary artery disease, particularly in patients with poor left ventricular function, shows immediate improvement after coronary artery bypass grafting. We studied 60 consecutive patients with aortic stenosis and mitral regurgitation to determine the degree of improvement in mitral regurgitation after aortic valve replacement alone versus aortic valve replacement combined with coronary artery bypass grafting. Thirty-six of the patients had normal coronary arteries (Group 1); the other 24 had symptomatic coronary artery disease requiring bypass surgery (Group 2). Echocardiography was performed preoperatively, 1 week postoperatively, and at follow-up. In Group 1, left ventricular ejection fraction did not improve early or at 2.5 months postoperatively, but mitral regurgitation improved gradually during follow-up. In Group 2, mitral regurgitation showed improvement 1 week postoperatively (p < 0.001), and left ventricular ejection fraction was improved at 2.5 months. We conclude that patients with aortic valve stenosis and mild-to-severe mitral regurgitation, without echocardiographic signs of chordal or papillary muscle rupture and without coronary artery disease, should undergo aortic valve replacement alone. The mitral regurgitation will remain the same or improve. For patients with coexisting coronary artery disease, simultaneous aortic valve replacement and coronary artery bypass grafting are imperative; however, the mitral valve again requires no intervention, since mitral regurgitation improves significantly after the other 2 procedures.

Adult↗
PubMed1999

Optimal timing of preoperative intraaortic balloon pump support in high-risk coronary patients.

BACKGROUND: Beneficial effects of preoperative intraaortic balloon pump (IABP) treatment, on outcome and cost, in high-risk patients who have coronary artery bypass grafting have been demonstrated. We conducted a prospective, randomized study to determine the optimal timing for preoperative IABP support in a cohort of high-risk patients. METHODS: Sixty consecutive high-risk patients who had coronary artery bypass grafting (presenting with two or more of the following criteria: left ventricular ejection fraction less than 0.30, unstable angina, reoperation, or left main stenosis greater than 70%) entered the study. Thirty patients did not receive preoperative IABP (controls), 30 patients had preoperative IABP therapy starting 2 hours (T2), 12 hours (T12), or 24 hours (T24), by random assignment, before the operation. Fifty patients had preoperative left ventricular ejection fraction mean, less than 0.30 (less than 0.26+/-0.08), (n = 40) unstable angina, 28% (n = 17) left main stenosis, and 32% (n = 19) were reoperations. RESULTS: Cardiopulmonary bypass was shorter in the IABP groups. There was one death in the IABP group and six in the control group. The complication rate for IABP was 8.3% (n = 5) without group differences. Cardiac index was significantly higher postoperatively (p<0.001) in patients with preoperative IABP treatment compared with controls. There were no significant differences between the three IABP subgroups at any time. The incidence of postoperative low cardiac output was significantly lower in the IABP groups (p<0.001). Intubation time, length of stay in the intensive care unit and the hospital was shorter in the IABP groups (p = 0.211, p<0.001, and p = 0.002, respectively). There were no differences between the IABP subgroups in any of the studied variables. CONCLUSIONS: The beneficial effect of preoperative IABP in high-risk patients who have coronary artery bypass grafting was confirmed. There were no differences in outcome between the subgroups; therefore, at 2 hours preoperatively, IABP therapy can be started.

Aged↗
PubMed1999

Preoperative lipid-control with simvastatin reduces the risk of postoperative thrombocytosis and thrombotic complications following CABG.

OBJECTIVE: It has earlier been suggested that postoperative thrombocytosis frequently occur after coronary artery bypass grafting (CABG) and may be linked to lipid disturbances. A prospective randomized study was undertaken to evaluate if preoperative lipid-control, using HMG-CoA-reductase inhibitor (Zocor), simvastatin, reduces the risk of postoperative thrombocytosis. METHODS: Seventy-seven patients with symptomatic coronary artery disease and hypercholesterolemia (total cholesterol > or =6.2 mmol/l), planned for CABG where randomly assigned to; undergo CABG without preoperation lipid control (group I, n = 37) or undergo simvastatin-treatment (20 mg daily) to control their lipids (4 weeks) prior to CABG (group II, n = 40). RESULTS: Patient characteristics and operation data did not differ between the groups. Serum-cholesterol, cholesterol/HDL-cholesterol, LDL-cholesterol, Apolipoprotein A1 and Plasminogen were all significantly higher in group I patients compared with group II just prior to surgery. Other laboratory parameters did not differ. RESULTS: In group II, total cholesterol and cholesterol/HDL-cholesterol quota were significantly lowered by simvaststin (-2 and -29%, respectively). Postoperative thrombocytosis (platelet counts > or =400000/microl) occurred significantly more frequently in group I 81% (30/37) compared with 3% (1/40) in group II, P<0.0001. Myocardial infarction after the 7th postoperative day was more often diagnosed in group I, 14 vs. 0% in group II. Postoperative transient renal failure occurred also more frequently in group I, 24% compared with 8% in group II. Other postoperative complications and laboratory data did not differ. CONCLUSIONS: This study once again underlines the importance of lipid control using HMG-CoA-reductase inhibitors (e.g. Zocor) in patients with established coronary artery disease. For the first time it is shown that lipid-control with simvastatin prior to CABG reduces the risk of postoperative thrombocytosis, thus lowers the risk for thrombotic complications.

Aged↗
PubMed1999

The influence of age on the outcome of primary coronary artery bypass grafting.

BACKGROUND: With the steady increase in the number of elderly patients requiring coronary artery bypass grafting (CABG), scepticism still exists as to whether this operation is justified in older patients or not, and whether there is an upper age limit. The aim of this study was to examine the effects of increasing age on the outcome of CABG. METHODS: A retrospective review was performed on 2127 consecutive patients undergoing primary CABG from January 1990 through June 1996. The patients were arbitrarily divided into age groups: 69 years or less (n=1607), 70-75 years (n=371), 76-80 years (n=129) and older than 80 years (n=20). Mortality, morbidity and long-term survival for each group was compared. RESULTS: The groups containing the elderly patients showed an over-representation of women, as well as a higher frequency of arterial hypertension, hyperlipidemia, previous infarction and diabetes. More patients, amongst the elderly, had unstable angina and diffuse coronary disease requiring urgent surgery and coronary thrombendarterectomy compared to those <70 years. Hospital mortality did not differ between the groups, 1.8, 3.0, 2.3 and 5.0%. There was an increased incidence of low postoperative cardiac output and a higher incidence of gastro-intestinal complications amongst the elderly. The 5-year survival was 92.2% (<70 years), 87.0% (70-75 years) and 86.3% (76-80 years) and the cardiac event-free survival was 87.5% (<70 years), 78.4% (70-75 years) and 80.8% (76-80 years) at 5 years. CONCLUSIONS: An acceptable early mortality and medium-term survival (5 years) together with excellent functional medium-term results support the justification of primary CABG in older patients irrespective of age.

Adult↗
PubMed1998

Late pseudoaneurysm formation after repair of the descending aorta.

We report a case of a 71-year-old hypertensive female patient presenting with haemoptysis and retrosternal pain from a leaking pseudo-aneurysm associated with a Dacron onlay patch used to repair a coarctation of the aorta 27 years earlier. This case illustrates a late and potentially fatal complication of this type of operation and describes a recent technique to reach the exact diagnosis and location of the aneurysm.

Aged↗
PubMed1998

Inflammatory response and oligo-element alterations following cardiopulmonary bypass in patients undergoing coronary artery bypass grafting.

Oligo-elements such as zinc (Zn), selenium (Se) and copper (Cu) have a significant influence on the function of the immune system. Various immunological and inflammatory changes are known to occur in patients undergoing cardiopulmonary bypass. The aim of this study was to evaluate changes in serum oligo-elements levels during and following cardiopulmonary bypass. The serum levels of Zn, Se and Cu were determined in 67 consecutive patients, with coronary artery disease admitted for coronary artery bypass grafting. Blood samples for oligo-elements, analysis were withdrawn into metal-free tubes just prior to the start of cardiopulmonary bypass; at 30, 60 and 90 min into cardiopulmonary bypass; following weaning from cardiopulmonary bypass; 30 min after termination of cardiopulmonary bypass; at 24 h; and on the 5th postoperative day. Trace elements analyses were performed using atomic absorption spectrophotometry. Interleukin 6 and 8, as well as serum albumin, creatine phosphokinase, lactate dehydrogenase and creatine phosphokinase-MB fractions were also analyzed. The mean age was 63 +/- 9 years and 91% (61) were men. The mean preoperative left ventricular function was 52 +/- 12%, Canadian Cardiovascular Society (CCS) angina class was 3.7 +/- 0.5 and 30% (20) of the operations were re-do's. All patients had normothermic cardiopulmonary bypass. Mean cardiopulmonary bypass-time was 85 +/- 31 min. One patient was lost for the recovery sampling (hospital mortality, 1.5%). Nine patients had a postoperative cardiac index < 2.0 liter/min per m2, which required pharmacological support and additional intra-aortic balloon pump in two of them. Other postoperative complications were few. There was a rapid depletion of S-selenium and S-Zn levels, which were halved at 30 min after cardiopulmonary bypass and remained low throughout the study period. The Cu/Zn ratio increased significantly at the start of cardiopulmonary bypass, which indicated an inflammatory reaction and was not normalized until the 5th postoperative day. Length of ischemia time, presence of diabetes. hypertension and hyperlipidemia did not influence the results, while a prolonged cardiopulmonary bypass-time > 120 min resulted in a higher Cu/Zn ratio than observed for shorter cardiopulmonary bypass-times. This indicates a more profound inflammatory response. Inflammatory parameters responded in the same manner as described earlier by others. These data indicate that severe loss of various oligo elements occur in patients undergoing coronary artery bypass grafting and suggests that a supplementary administration of zinc and perhaps also selenium could be appropriate during cardiopulmonary bypass.

Adult↗
PubMed1998

Sequential vein bypass grafting: tactics and long-term results.

The sequential bypass grafting technique has many advantages over coronary artery bypass grafting with single grafts. The aim of this study was to evaluate the consequences of sequential bypass graft failure. Between 1 January 1984 and 31 December 1996, 3846 patients underwent primary coronary artery bypass vein grafting. A total of 3490 patients received sequential vein bypass grafts and 356 patients received single vein bypass grafts (9%). There were 6177 sequential bypass grafts (3490 postero-lateral grafts (56%) and 2687 in the antero-lateral position (44%)) and 1468 single grafts (972 vein grafts and 496 internal thoracic artery grafts). Overall, there were 80 hospital deaths (2.1%). Mortality in relation to type of grafts used was: 13 deaths in 356 patients with only single graft (3.7%) and 67 deaths in 3490 patients who received sequential vein grafts (1.9%). Of 3766 hospital survivors, 3731 were followed for an average of 76 months. During follow-up, 85 patients died (2.3%), 15 patients (0.4%) underwent cardiac transplantation and 52 (1.4%) had re-do coronary artery bypass vein grafting. Graft-percutaneous transluminal coronary angioplasty was performed in 56 patients (1.5%), 37/1390 single bypass grafts (2.7%) and 19/6023 sequential bypass grafts (0.3%). There were 272/6023 symptomatic sequential graft occlusions (4.5%) (182 were in postero-lateral position and 90 in the antero-lateral position). There were 66/667 single vein graft occlusions (9.9%) and 15 symptomatic internal thoracic artery graft occlusions (2.1%) during follow-up. In 97% of patients, presenting symptoms of postero-lateral sequential bypass graft occlusion took the form of a renewed angina with a myocardial infarction rate of 3% and a mortality rate of 7%. Corresponding figures for antero-lateral sequential bypass grafts were 22, 78 and 68%, and anterior single vein bypass grafts were 70, 30 and 15%, respectively. The overall 10-year survival rate in patients with sequential bypass grafts was 81.2% and the cumulative patency rate (1464 angio-controls of 2576 sequential vein grafts) was 72.2%. A symptomatic occlusion of a postero-lateral sequential vein bypass results in a low incidence of myocardial infarction with low mortality, when the terminal anastomosis is connected to a high flow vessel. An antero-lateral sequential vein bypass graft has better long-term patency than single vein bypass, but should occlusion occur, it would usually be associated with a higher myocardial infarction and mortality rates than a single vein graft. The highest risk for failure of a sequential graft in the antero-lateral position occurs when the left anterior descending artery (LAD) is small or severely diseased. In this situation the single graft technique with internal thoracic artery appears to be safer.

Adult↗
PubMed1998

[Symptomatic coronary disease associated with mitral insufficiency: surgical strategy].

In recent years coronary artery bypass grafting (CABG) has been extended to include patients with very low left ventricular ejection fractions (LVEF), also frequently with co-existing mild to moderate mitral valve regurgitation (MR). The question is, should MR be corrected simultaneously with a myocardial revascularization or not? Between January 1990 and December 1996, 82 patients with preoperative LVEF < or = 0.25 and echocardiographic evidence of co-existing MR without chordal or papillary muscle rupture (Grade I-28%, II-35%, III-32% and IV-5%) underwent primary CABG. None of them underwent simultaneous mitral valve surgery. The mean preoperative LVEF was 0.17 +/- 0.04 (0.10-0.25), mean PAP 43.8 +/- 15.9 mmHg. An average of 4.4 +/- 1.5 grafts/ patient were placed. The overall mortality was 3.7% (3/82). Transient postoperative low cardiac output syndrome occurred in 24 patients (29%). Thirty-two patients (39%) had no postoperative complications at all. Seventy-nine hospital survivors were followed up over a period of 18 months (6-48 months) on average. There was one death (8 months post-operatively) and 2 graft occlusions, not requiring redo surgery. At the end of follow up echocardiography showed that 45 patients had no MR at all and 28 patients had MR-Grade I, a total of 73 patients (94%). Five patients had Grade II-III MR, none of them requiring mitral valve surgery. All patients improved their NYHA functional class, from 3.5 +/- 0.7 to 1.8 +/- 0.5 and the LVEF from 0.17 +/- 0.04 to 0.46 +/- 0.08, p < 0.001. Moderate to severe co-existing MR (Grade II-IV) seems to normalize after the myocardial revascularization and should therefore not be surgically corrected at the primary operation, if there are no echocardiographic evidence of chordal or papillary muscle rupture. Peroperative control echocardiography is recommended.

Adult↗