Search PubMed⌕ Search

Biomedical subjects

Jan T Christenson

Publications and source records attributed to Jan T Christenson.

18 recordsLinked to original sources
PubMed2006

Long-term outcome after surgical intervention and interventional procedures for the management of Takayasu's arteritis in children.

OBJECTIVE: There is little information available on the results of reconstructive arterial surgery for Takayasu's arteritis in children. This study evaluates midterm to long-term outcome after surgical, as well as interventional, procedures. METHODS: From 1984 through 2004, 10 children (5 boys and 5 girls; age, 12.7 +/- 2.6 years) with Takayasu's arteritis were referred to our center. Baseline cardiovascular assessment included contrast angiography (n = 4), magnetic resonance imaging-angiography (n = 3), and combined contrast angiography plus magnetic resonance imaging-angiography (n = 3). Two patients had disease confined to the thoracic aorta, 4 had disease confined to the abdominal aorta, and 4 had combined thoracoabdominal aortic disease. Steno-occlusive lesions were predominant in 92% of cases. Seven patients were maintained on steroid therapy throughout the follow-up period. Eight children underwent complex surgical procedures, 1 patient had balloon dilatation of the renal and mesenteric arteries, and 1 patient had combined vascular surgery with percutaneous transluminal angioplasty. Overall, 24 grafts (polytetrafluoroethylene, Dacron grafts, and cryopreserved homografts) were implanted in various locations. RESULTS: There were no perioperative deaths. Arterial hypertension regressed in all patients, and cardiac function normalized in all 4 patients with dilative cardiomyopathy. Over a 20-year period, 1 patient presented with sudden death and 2 showed nonfatal disease progression, one of whom required surgical reintervention. The occlusion rate was higher in Dacron grafts. CONCLUSIONS: Our study shows that despite the extent and severity of vascular lesions, children with Takayasu's arteritis could benefit from reconstructive surgery, with low mortality, morbidity, and satisfactory long-term results.

Adolescent↗
PubMed2005

Invited commentary.

Explore the source record for details and available documents.

Heart Arrest, Induced↗
PubMed2005

Intra-aortic filtration: capturing particulate emboli during aortic cross-clamping.

Particulate emboli are an important factor in the development of complications after cardiac surgery. The use of an intra-aortic filter during aortic declamping has proved safe and effective in reducing the incidence of embolic complications. Because aortic cross-clamping is also associated with the risk of embolism, we measured the release of particulate emboli at the time of aortic cross-clamping and at declamping. We deployed intra-aortic filters (Edwards EMBOL-X Slim Protection System) at 2 different times during 15 consecutive cardiac procedures with cardiopulmonary bypass. Filter A was inserted before aortic cross-clamping and left in place for a mean time of 3 minutes, and Filter B was inserted before aortic declamping for a mean of 17 minutes. An independent institution performed histopathologic examination. All filters captured particulate emboli, independent of the patients' degree of proximal aortic atherosclerotic disease. Macroscopy showed that Filter A captured more particles (mean, 70 +/- 2.6) in 7 of 15 patients (46.7%), Filter B captured more particles (mean, 6.7 +/- 2.6) in 5 of 15 patients (33.3%), and the filters captured the same number in 3 of 15 patients (20%). Microscopy showed that both filters captured fibrous atheroma or fibrous cap in 10 of 15 patients. We observed no complications related to the use of the filters. Aortic cross-clamping is associated with a high risk of embolism. We suggest that optimal protection against embolism during cardiac surgery can be achieved by applying intra-aortic filtration not only before aortic declamping but also before aortic cross-clamping.

Aged↗
PubMed2004

In-hospital mortality associated with the use of intra-aortic balloon counterpulsation.

We analyzed in-hospital mortality for patients treated with intra-aortic balloon counterpulsation from the Benchmark Counterpulsation Outcomes Registry (n = 25,136). In-hospital mortality was higher in patients who received only medical interventions (32.5%) than in those who underwent percutaneous (18.8%) and surgical (19.2%) interventions, and was greatest in the first days after hospital admission for all 3 intervention types. Therefore, diagnostic evaluation and treatment decisions should be made as early as possible, and physicians should be aware of associated risk factors in making choices for patients.

Aged↗
PubMed2004

Blood group incompatibility and accelerated homograft fibrocalcifications.

OBJECTIVE: Cryopreserved valved homograft has become the conduit of choice for right ventricular outflow tract reconstruction in pediatric cardiac surgery. Aortic homografts have been frequently used in pulmonary position, but accelerated aortic homograft fibrocalcification may occur. Blood group incompatibility between receiver and homograft donor may play a central role in this context. METHODS: Between 1993 and 2000, 59 children (mean age 6.4 +/- 4.4 years) received cryopreserved valved homografts for right ventricular outflow tract reconstruction and were followed from 2 to 10 years clinically, with echocardiography and chest radiography for detection of development of homograft calcifications. Seventeen patients were 3 years or younger. Fifty aortic (85%) and 9 pulmonary homografts were all used in pulmonary position. Thirty-three patients (56%) had the same blood group (ABO) as the homograft donor (iso group), and 26 were blood group-incompatible (non-iso group). RESULTS: No deaths occurred during follow-up. Six patients (10.2%) required homograft replacement because of severe fibrocalcifications, and another 3 showed moderate homograft calcifications (5.1%) at last examination. Freedom from moderate to severe homograft calcification at 8 years (Kaplan-Meier) was 95.2% for the iso group and 72.9% for the non-iso group (P <.0001). Homograft calcifications occurred within 2 years of implantation in 6/9 patients (67%) in the non-iso group. CONCLUSIONS: Blood group incompatibility between receiver and homograft donor seems to play an important role in the development of accelerated fibrocalcifications in cryopreserved homografts, particularly in the very young (3 years old or younger). Blood group compatibility should therefore be respected to avoid accelerated homograft fibrocalcifications.

Aortic Valve↗
PubMed2004

Repair of aortic coarctation using temporary ascending to descending aortic bypass in children with poor collateral circulation.

Aortic coarctation can now be repaired surgically with excellent results. Even though rare, injury to the spinal cord resulting in paraplegia remains a major concern. Preoperative evaluation showing the absence of collateral circulation is valuable in order to introduce protective actions. This report describes our experience using a temporary bypass from the ascending to the descending aorta bypass in children undergoing surgical correction of aortic coarctation in the setting of poorly developed collateral circulation. Between 1990 and 2002, we undertook direct surgical repair in 56 patients with isolated aortic coarctation, 20 as neonates, 11 as infants, and 25 during childhood. From 1998 onwards, we introduced preoperative evaluation of the collateral circulation with magnetic resonance imaging. From that time, we placed a temporary bypass from the ascending to the descending aorta, using a polytetrafluoroethylene tube of 4 to 8 mm diameter, whenever distal pressures were shown to be 25 mmHg or less after test clamping, or when magnetic resonance imaging revealed absence of collateral circulation. We found excellent correlations between the direct intra-operative measurements of distal pressure and the findings at magnetic resonance imaging. Following introduction of the temporary bypass, we observed no neurological complications, nor were there any complications related to bypass. Freedom from restenosis was 96%. Preoperative magnetic resonance imaging, therefore, can accurately visualize poor collateral circulation in children with aortic coarctation. The use of a temporary bypass can possibly eliminate the risk of neurological sequels following direct repair of coarctation in children with poorly developed collateral circulation. The temporary bypass is both easy to apply and safe.

Adolescent↗
PubMed2004

Bentall procedure using cryopreserved valved aortic homografts: mid- to long-term results.

The Bentall procedure is the standard operation for patients who have lesions of the ascending aorta associated with aortic valve disease. In many cases, however, mechanical prosthetic conduits are not suitable. There are few reports in the English-language medical literature concerning the mid- to long-term outcome of Bentall operations with cryopreserved homografts. Therefore, we reviewed our experience with this procedure and valved homografts. From January 1997 through December 2002, 21 patients underwent a Bentall operation with cryopreserved homografts at our institution. There were 14 males and 7 females; the mean age was 36 +/- 21 years (range, 15-74 years). Eleven patients had undergone previous aortic valve surgery. All patients had aortic dilatation or aneurysms involving the ascending aorta. Indications for surgery included aortic valve stenosis or insufficiency, and aortic valve endocarditis (native valve or prosthetic). One patient had Takayasu's arteritis and 3 had Marfan syndrome. There was 1 hospital death (due to sepsis), but no other major postoperative complications. The mean hospital stay was 14 +/- 7 days. Follow-up echocardiographic and computed tomographic scans were performed yearly. The mean follow-up was 34 months (6-72 months). Follow-up imaging revealed no calcifications or degenerative processes related to the homograft. Four patients had minimal valve regurgitation. Two patients died during follow-up. The 3-year actuarial survival rate was 85.7%. Our data suggest that the Bentall procedure with a valved homograft conduit is a safe procedure with excellent mid- to long-term results, comparable to results reported with aortic valve replacement with a homograft.

Adolescent↗
PubMed2003

Contemporary utilization and outcomes of intra-aortic balloon counterpulsation in acute myocardial infarction: the benchmark registry.

OBJECTIVES: We sought to examine contemporary utilization patterns and clinical outcomes in patients with acute myocardial infarction (AMI) requiring intra-aortic balloon pump (IABP) counterpulsation. BACKGROUND: Despite increasing experience with and broadened indications for intra-aortic counterpulsation, the current indications, associated complications, and clinical outcomes of IABP use in AMI are unknown. METHODS: Between June 1996 and August 2001, data were prospectively collected from 22,663 consecutive patients treated with aortic counterpulsation at 250 medical centers worldwide; 5,495 of these patients had AMI. RESULTS: Placement of an IABP in AMI patients was most frequently indicated for cardiogenic shock (27.3%), hemodynamic support during catheterization and/or angioplasty (27.2%) or prior to high-risk surgery (11.2%), mechanical complications of AMI (11.7%), and refractory post-myocardial infarction unstable angina (10.0%). Balloon insertions were successful in 97.7% of patients. Diagnostic catheterization was performed in 96% of patients, and 83% underwent coronary revascularization before hospital discharge. The in-hospital mortality rate was 20.0% (38.7% in patients with shock) and varied markedly by indication and use of revascularization procedures. Major IABP complications occurred in only 2.7% of patients, despite median use for three days, and early IABP discontinuation was required in only 2.1% of patients. CONCLUSIONS: With contemporary advances in device technology, insertion technique, and operator experience, IABP counterpulsation may be successfully employed for a wide variety of conditions in the AMI setting, providing significant hemodynamic support with rare major complications in a high-risk patient population.

Adult↗
PubMed2003

Intra-aortic balloon counterpulsation in US and non-US centres: results of the Benchmark Registry.

AIMS: To examine differences in patient characteristics and outcomes in 19636 patients enrolled in the USA and 3027 patients enrolled in other countries undergoing intra-aortic balloon pump (IABP) counterpulsation. METHODS AND RESULTS: Indications for IABP use; a larger percentage of US patients were identified as 'early support and stabilization for angiography or angioplasty' (21.1% US vs 11.8% non-US), and 'pre-operative support for high-risk CABG' (15.9% vs 6.6%). A smaller percentage of US patients vs non-US patients were identified as 'weaning from cardiopulmonary bypass' (14.3% vs 28.2%), and 'refractory ventricular failure' (6.2% vs 9.8%). One out of five patients in both groups was listed as 'cardiogenic shock' (18.9% US vs 20.2% non-US). All cause, risk-adjusted, in-hospital mortality (20.1% vs 28.7%; P<0.001), and mortality with IABP in place (10.8% vs 18.0%; P<0.001) were lower at US vs non-US sites. In both US and non-US institutions, IABP associated complication rates, such as IABP-related mortality (0.05% vs 0.07%), major limb ischaemia (0.9% vs 0.8%), and severe bleeding (0.9% vs 0.8%), were low. CONCLUSIONS: IABP counterpulsation is deployed at an earlier clinical stage in US patients. Mortality rates are higher for non-US patients, particularly for patients with non-surgery cardiac interventions, even after adjusting for risk factors. Complication rates were low. Physicians should therefore not be reluctant to use IABP in high-risk patients undergoing cardiac procedures.

Aged↗
PubMed2003

Undiagnosed aberrant right subclavian artery: pitfall in aortic arch surgery.

Selected cerebral perfusion as brain protection via right subclavian artery during aortic arch aneurysm repair adds safety, but may be jeopardized by aortic arch anomalies not readily recognized preoperatively. We describe a case of transverse aortic arch aneurysm repair where an undiagnosed aberrant right subclavian artery was cannulated for selective brain protection.

Aged↗
PubMed2002

How to diminish reoperation rates after initial repair of tetralogy of Fallot?

BACKGROUND: Complete correction of tetralogy of Fallot has good long-term results. Right ventricular outflow tract obstruction and pulmonary insufficiency occur which require reintervention. The present study evaluated the efficacy of reoperation following complete correction of tetralogy of Fallot, the sites of recurrences and impact of techniques used at first operation. METHODS: Between 1980 and 1999, 501 patients underwent complete correction of tetralogy of Fallot. Reoperation rate was 7.4%. Residual or recurrent right ventricular outflow tract stenosis was seen in 25 patients (68%), and 7 patients (19%) had severe pulmonary insufficiency. Age at redo was 9.1+/-6.4 years. Restenosis was most frequently observed (75%) at the bifurcation of the pulmonary artery. Extended 1-patch enlargement was used until 1989 and thereafter changed to a 2-patch technique. RESULTS: Valvar-supravalvar 1-patch technique had a redo rate of 33.3%, compared with 4.3% for the 2-patch technique, p = 0.0264, with excellent freedom from reoperation rate. At reoperation right ventricular-pulmonary artery (RV-PA) conduits managed 29 patients and 3 had supravalvar patch enlargement. Hospital mortality was 5.4% (2 of 37). Twenty-five patients (68%) were in New York Heart Association functional class I to II at end of the follow-up, and none required further interventions. CONCLUSIONS: Redo rate following complete correction of tetralogy of Fallot was 7.4%. Right ventricular outflow tract pathology was the dominant reason for reoperations (86%). At reoperation, RV-PA conduits was the most frequently used technique. Reoperation was efficient in reducing the RV-PA gradient, had low hospital and late mortality. A 2-patch valvar-supravalvar enlargement at first operation reduced the risk for redo in long-term follow-up.

Adolescent↗
PubMed2002

Trends in intraaortic balloon counterpulsation complications and outcomes in cardiac surgery.

BACKGROUND: As the proportion of high-risk patients for cardiac surgery increases, use of intraaortic balloon counterpulsation (IABC) has increased, especially in preoperative therapy. Although the efficacy and cost-effectiveness of IABC have been demonstrated, historically higher complication rates have dissuaded some practitioners from using IABC. METHODS: This report describes IABC use in cardiac surgery, examines trends in complications over time, and compares outcomes in preoperative versus postoperative use in a single prospective worldwide registry over the past 3 years. RESULTS: The frequency of IABC use appears to be increasing with time as the complication rates have dramatically fallen. The overall IABC-related complication rate was 6.5% (460/7,101), and the rate of major complications (requiring surgery or transfusion) was 2.1% (148/7,101). Hospital mortality was significantly lower in patients treated preoperatively with IABC compared with patients treated postoperatively (8.8% vs 28.2%, p < 0.0001), although this may be due to a selection bias in the postoperative group. CONCLUSIONS: Preoperative IABC therapy leads to better patient outcomes in high-risk CABG patients. Improved IABC technology and better surveillance have led to increased use with lower complication rates. Although selection bias is inherent in retrospective studies, the Benchmark Counterpulsation Outcomes Registry outcomes are in close concordance to prospective randomized studies previously reported.

Cardiac Surgical Procedures↗
PubMed2002

Regional extra-corporeal circulation to protect transplanted kidney and pancreas from ischemia during vascular reconstruction.

The development of severe aorto-ilio-femoral atherosclerotic disease in a patient with a previous double transplantation, kidney and pancreas, is a major surgical challenge. The transplanted organs have to be protected from extensive ischemia during the vascular reconstructive procedure and achieve optimal revascularization. The surgical management of a complex case where regional extra-corporeal circulation was used to protect transplanted pancreas and kidney during aorto-bifemoral vascular grafting in a 39 yr old diabetic patient is described. Regional femoro-femoral extra-corporeal circulation with an oxygenator is a safe technique that allows time for the proximal revascularization, minimizes the warm organ ischemia time and results in preservation of organ function.

Adult↗
PubMed2002

Preoperative intraaortic balloon pump for salvage myocardial revascularization.

The benefit of preoperative intraaortic balloon pumping on hospital and 1-year mortality was assessed in 17 consecutive patients with cardiogenic shock who underwent salvage coronary artery bypass surgery between January 1996 and May 2000. Mean preoperative cardiac index was 1.57 +/- 0 23 L.min(-1).m(-2). Hemodynamic stability was achieved prior to surgery in 14 patients, and mean cardiac index increased to 2.28 +/- 0.64 L.min(-1).m(-2). Hospital mortality was 5.9% (1 patient). Five patients required postoperative intraaortic balloon pumping because of low cardiac output. The duration of intensive care, hospital stay, and the total procedural cost were similar to those reported for high-risk coronary bypass grafting. Cardiac event-free survival was 88.2% (15/17) at 1 year. Intraaortic balloon pumping promises to be an effective therapy for patients in cardiogenic shock who subsequently undergo surgical myocardial revascularization as a salvage procedure.

Aged↗
PubMedDate not supplied

The role of intra-aortic counterpulsation in high-risk OPCAB surgery: a prospective randomized study.

BACKGROUND: High-risk patients would benefit the most of OPCAB revascularization. This prospective and randomized study evaluates the efficacy and safety of pre- and perioperative IABC in high-risk OPCAB. MATERIAL: Group A-IABC started prior to induction of anesthesia (n = 15); group B-no preoperative IABC (n = 15). Adult high-risk coronary patients to undergo OPCAB. High risk = (minimum 2) EF < 0.30, left main stenosis, unstable angina, redo. Bailout if hemodynamic instability CPB or IABC in group B. Study endpoints (a) cardiac protection (troponin 1, cardiac index (CI), ECG), (b) inflammatory response (lactate, IL-6), (c) clinical outcome (mortality, morbidity). Emergency operations 33%, re-operation 13%, unstable angina 100%, left main 60% and EF 0.29, without group differences. RESULTS: No bailout group A, 10 in group B, p < 0.0001. Postoperative IABC six (group A) and seven patients (group B), during 6.8 +/- 5.1 hours (group A) versus 41.2 +/- 25.5 hours (group B), p = 0.0110. Myocardial protection without group differences, but CI significantly better in group A. Inflammatory response significantly less in group A. CLINICAL OUTCOMES: one death, one MI and two renal failure in group B, none in group A. Intensive care unit (ICU) stay 27 +/- 3 hours (group A) versus 65 +/- 28 hours (group B), p = 0.0017. LOS 8 +/- 2 days (group A) versus 15 +/- 10 (group B), p = 0.0351. No IABC related complications. CONCLUSIONS: Pre- and perioperative IABC therapy offers efficient hemodynamic support during high-risk OPCAB surgery, lowers the risk of hemodynamic instability, is safe and shortens both ICU and hospital length of stay significantly, and is a cost-effective therapy.

Cardiopulmonary Bypass↗
PubMedDate not supplied

Changing surgical management for acute aortic dissections type a improves immediate outcomes.

BACKGROUND: Surgical treatment of acute aortic dissection type A is well established. This study analyzes the impact of changing surgical management of Type A dissections on hospital mortality and postoperative complications. METHOD: Between January 1980 and December 2002, 141 consecutive patients were operated for acute Type A aortic dissection. Patients were analyzed in 3 time periods; 1980-1989, n = 26, 1990-1999, n = 71 and 2000-2002, n = 44). Antegrade cerebral perfusion via subclavian cannulation, a more extensive resection as well as valvar repair was introduced as routine procedures from January 2000. RESULTS: Mortality and neurological complications decreased over time; from 31% to 9.1% and from 27% to 2.5%, respectively. During follow-up, 14 patients (12%) required surgical re-intervention for aneurysms (1 to 17 years later) with associated hospital mortality of 21%. CONCLUSIONS: Antegrade cerebral perfusion reduces neurological complications and more extensive surgical approach did not increase mortality and morbidity.

Acute Disease↗