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Biomedical subjects

Tomislav Mihaljevic

Publications and source records attributed to Tomislav Mihaljevic.

At least 37 records · Page 2Linked to original sources
PubMed2004

Outcomes in patients with normal serum creatinine and with artificial renal support for acute renal failure developing after coronary artery bypass grafting.

This retrospective study of cardiac surgical patients with normal serum creatinine who developed acute renal failure requiring artificial renal support was undertaken to (1) determine the prevalence of acute renal failure and hospital mortality in this subgroup, (2) identify the independent predictors of early mortality, and (3) determine long-term survival and prognosis.

Acute Kidney Injury↗
PubMed2004

Transesophageal echocardiography for detecting extrapulmonary thrombi during pulmonary embolectomy.

BACKGROUND: Pulmonary embolectomy is an evolving surgical procedure for the treatment of severe pulmonary embolism. In addition to removing pulmonary thromboemboli, the achievement of optimal results also requires identification and extraction of intrathoracic, extrapulmonary thromboemboli from the right atrium, right ventricle, and the superior or inferior vena cava. Otherwise, these thromboemboli may become the source of recurrent pulmonary embolism. Intraoperative transesophageal echocardiography is frequently used during pulmonary embolectomy as a guide for the surgeon and a monitor of cardiac performance. However, its utility for detecting concurrent intrathoracic, extrapulmonary thromboemboli has not been thoroughly investigated. METHODS: The study population included 50 consecutive patients undergoing emergent pulmonary embolectomy. Results from preoperative diagnostic studies including transthoracic echocardiography; ventilation/perfusion scan, pulmonary angiography, and computed tomography were reviewed, along with the intraoperative echocardiographic reports for the presence of intrathoracic extrapulmonary thromboemboli. In addition, the surgical operative notes were consulted to determine the impact of intraoperative transesophageal echocardiography on surgical decision making. RESULTS: Extrapulmonary intrathoracic thromboemboli were identified preoperatively in 8 patients (16%). Intraoperatively, thromboemboli were identified in 5 additional patients by transesophageal echocardiography, adding to a total of 13 patients with extrapulmonary thrombi (26%). Intraoperative transesophageal echocardiography provided the sole source of evidence that directed surgical management in 10% (5 of 50) of all patients undergoing pulmonary emboletcomy. CONCLUSIONS: Intraoperative transesophageal echocardiography identified intrathoracic, extrapulmonary thomboemboli in 26% of patients undergoing pulmonary embolectomy, resulting in an alteration of surgical management in 10% of patients. These findings support the critical role of intraoperative echocardiography during pulmonary embolectomy.

Adult↗
PubMed2004

Severity of intraoperative tricuspid regurgitation predicts poor late survival following cardiac transplantation.

BACKGROUND: This study evaluates the significance of tricuspid regurgitation (TR) on long-term survival as detected by intraoperative transesophageal echocardiography at the time of orthotopic heart transplantation. Although significant (2+ to 4+) TR after orthotopic heart transplantation is rare, its influence on long-term survival is unknown, warranting further investigation. METHODS: Between January 1992 and July 2001, 181 consecutive patients underwent orthotopic heart transplantation. Tricuspid regurgitation was graded by intraoperative transesophageal echocardiography after final separation from cardiopulmonary bypass in 130 of 181 patients (72%). RESULTS: Although 80% (104/130) of patients had either no (0, n = 77) or trace (1+, n = 27) TR, 9% (12/130 patients) had mild (2+), 10% (13/130 patients) had moderate (3+), and 0.8% (1/130 patients) had severe (4+) TR. The severity correlated strongly with the presence of right ventricular dysfunction (p < 0.001). In a multivariate regression model, gender mismatch (p = 0.002) and right ventricular dysfunction (p < 0.001) were independent predictors for equal to or greater than mild (2+ to 4+) TR (p = 0.015). Although the degree of recipient pulmonary vascular resistance did not influence the grade (p = 0.600), higher pulmonary vascular resistance tended to increase the severity of TR in the setting of prolonged donor ischemic times (p = 0.054). Proportional hazards regression analysis demonstrated significantly decreased survival for patients with mild or greater (2+ to 4+) TR detected by transesophageal echocardiography at the time of transplantation (p < 0.001) and RV dysfunction (p = 0.023). CONCLUSIONS: Even mild (> or = 2+) TR identified by transesophageal echocardiography at the time of orthotopic heart transplant predicts poor late survival, suggesting a possible role for concomitant tricuspid valve repair at the time of transplant. Whether or not tricuspid valve repair will improve long-term survival is unknown.

Acute Kidney Injury↗
PubMed2004

Risk factors and outcomes for 'vasoplegia syndrome' following cardiac transplantation.

OBJECTIVE: Vasoplegia syndrome after orthotopic heart transplantation (OHT) is a rare but highly lethal syndrome of unknown etiology, characterized by severe refractory hypotension, metabolic acidosis, and decreased systemic vascular resistance (SVR). The objective of this retrospective study was to identify the risk factors contributing to the development of vasoplegia syndrome after OHT in order to provide potential algorithms for its management. METHODS: Between October 1992 and July 2001, 187 consecutive patients underwent OHT. Complete pre- and post-data were available in 147 patients (78%). Mean age was 49+/-11 years, 82% (120/147) were male, and donor ischemic time was 117+/-62 min. Twenty-eight of 147 (19%) developed vasoplegia syndrome, defined as SVR <800 dyns per cm(5) with serum bicarbonate <20 mEq/l. RESULTS: Patients who developed vasoplegia syndrome demonstrated greater hospital mortality (25 vs. 9%, P=0.031) compared to those who did not. Multivariate logistic regression identified pre-operative use of intravenous heparin (OR 2.8, CI 1-7.4, P=0.039) and body surface area >1.9 m(2) (OR 7, CI 0.98-50, P=0.052) as independent predictors for the development of post-operative vasoplegia syndrome. Pre-operative use of inotropic support conferred protection against the development of post-operative vasoplegia syndrome (OR 0.25, CI 0.08-0.79, P=0.018). Pre-operative use of ACE inhibitors was not associated with increased risk (55 vs. 59%, P=0.441). CONCLUSIONS: Vasoplegia syndrome following OHT is associated with high early mortality. The development of a risk stratification profile may help in patient selection as well as the post-operative management of vasoplegia syndrome following OHT.

Acidosis↗
PubMed2004

Three-dimensional echocardiography-guided atrial septectomy: an experimental study.

OBJECTIVES: The surgical feasibility of beating-heart atrial septectomy under the guidance of two different types of real-time 3-dimensional echocardiography systems was examined. METHODS: A modified real-time 3-dimensional echocardiography system with a x4 matrix transducer (Sonos 7500; Philips Medical Systems, Andover, Mass) or a mechanical 1-dimensional array transducer (SSD-5500; Aloka Co, Ltd, Tokyo, Japan) was used. Small porcine atrial septal defects (n = 8) were enlarged with a Kerrison bone punch in the tank model. In the animal studies, small atrial septal defects (n = 8) were enlarged with the same device through a transatrial port. In both experiments, the area of the atrial septal defect measured by real-time 3-dimensional echocardiography was compared with the area measured directly. RESULTS: Real-time 3-dimensional echocardiography provided satisfactory images and sufficient anatomic detail for the atrial septectomy in both experimental settings. All the atrial septal defects were successfully enlarged; an increase of as much as 293% of the preoperative atrial septal defect area was achieved in the tank experiment, and an increase of as great as 449% of the preoperative area was achieved in the animal experiment. The size of the atrial shunt was increased significantly after the atrial septectomy relative to that before the surgery (P <.0001). The percentage enlargement of the atrial septal defect measured by real-time 3-dimensional echocardiography was strongly correlated with that measured directly (both r(2) = 0.997, P <.0001) Bland-Altman analysis showed close agreement between the results obtained by the two measurement methods in both models. CONCLUSIONS: Real-time 3-dimensional echocardiography provides satisfactory images and sufficient anatomic detail for atrial septectomy. This experiment demonstrates the surgical feasibility of a beating-heart intracardiac procedure such as atrial septectomy under real-time 3-dimensional echocardiographic guidance.

Animals↗
PubMed2004

Three-dimensional echocardiography-guided beating-heart surgery without cardiopulmonary bypass: a feasibility study.

BACKGROUND: There is no current acceptable approach for intracardiac beating-heart interventions. We have adapted real-time 3-dimensional echocardiography with specialized instrumentation to facilitate beating-heart repair of atrial septal defects and mitral valve plasty to investigate the feasibility of real-time 3-dimensional echocardiography-guided cardiac surgery. METHODS: In experiment I a modified real-time 3-dimensional echocardiography system with x4 matrix transducer was compared with 2-dimensional echocardiography in the performance of common surgical tasks. Completion times, deviation from an ideal trajectory, and an echogenic target were measured. In experiment II porcine atrial septal defects were closed with an original semiautomatic suturing device (n = 4) and with a 5-mm endoscopic stapler and a pericardial or polytetrafluoroethylene patch (n = 4). In experiment III a pulsatile porcine mitral valve model was developed, and suture placement through the anterior and posterior mitral leaflets was performed (n = 8). During all experiments, the operator was blinded to the target and operated on only with ultrasonic guidance. RESULTS: In experiment I, compared with 2-dimensional echocardiographic guidance, completion times improved by 21% ( P <.01) with high-trajectory accuracy, and suture deviation was significantly smaller (2-dimensional echocardiography, 5.4 +/- 2.7 mm; 3-dimensional echocardiography, 1.7 +/- 0.7 mm; P <.05) in real-time 3-dimensional echocardiography-guided tasks. In experiments II and III in both atrial septal defect closure and mitral valve plasty, real-time 3-dimensional echocardiography provided satisfactory images and sufficient anatomic detail for suturing and patch deployment. All surgical tasks were successfully performed with accuracy. CONCLUSIONS: Real-time 3-dimensional echocardiography provides adequate imaging and anatomic detail to act as a sole guide for surgical task performance. These initial experiments demonstrate the feasibility of beating-heart direct or patch closure of atrial septal defects and mitral valve plasty without cardiopulmonary bypass.

Animals↗
PubMed2004

One thousand minimally invasive valve operations: early and late results.

OBJECTIVE: We sought to evaluate the potential benefits of minimally invasive approaches for treatment of isolated aortic and mitral valve disease. METHODS: From 7/96 to 04/03, we performed 1000 minimally invasive valve operations: 526 aortic (AV) procedures (64 years; mean, 25-95) and 474 mitral (MV) procedures (58 years; mean, 17-90). RESULTS: In the AV group, an upper ministernotomy was used in 492/526 patients (93%) and a right parasternal approach in 34 (7%). Sixty-three patients had reoperative aortic valve replacements. In the MV group lower sternotomy was used in 260/474 (55%), right parasternal in 200/474 (42%), and a right thoracotomy in 14 patients. MV repair was performed in 416 and MV replacement in 58 patients. Operative mortality was 12/526 (2%) in the AV and 1/474 (0.2%) in the MV group. Freedom from reoperation at 6 years was 99% and 95% in the AV and MV group, respectively. Late mortality was 5% in the AV and 3% in the MV group, respectively. CONCLUSIONS: Minimally invasive valve surgery can be performed at very low levels of morbidity and mortality, with results equal to or better than conventional techniques. All forms of valve repair and replacement operations can be performed. Long-term survival and freedom from reoperation are excellent.

Adult↗
PubMed2004

Delayed presentation of totally avulsed right superior vena cava after extraction of permanent pacemaker lead.

Pacemaker lead extraction has been shown to be an effective and safe treatment for infected permanent pacemaker leads, however, they may lead to potentially serious complications, usually occurring during the extraction procedure. This report describes a case of a 48-year-old woman with a patent persistent left SVC and an infected permanent pacemaker lead of a DDD pacing system who underwent transvenous laser-assisted lead extraction using a combined SVC and femoral approach. Two days after the procedure the patient developed symptoms of SVC obstruction requiring surgical intervention. The right SVC was found to be almost completely destroyed with only a thin strip of the lateral wall intact and active bleeding. The probable causative mechanisms and surgical management are discussed.

Device Removal↗
PubMed2004

Aortic valve replacement in patients with severely reduced left ventricular function.

Aortic valve replacement (AVR) can be done safely in patients with severe aortic stenosis (AS) and depressed ventricular function (ejection fraction < or =35%). Dobutamine echocardiography is useful to identify AS patients with contractile reserve who will benefit from AVR and can be used for risk stratification of these patients. AVR can also be undertaken in patients with severe aortic regurgitation and depressed ventricular function with an acceptable operative mortality. AVR in both groups results in a 5-year survival of approximately 70%, which is similar to that of orthotopic heart transplantation. Due to the comorbidities of immunosuppression and limited donor organ supply, AVR should be attempted prior to transplantation in both these high-risk groups.

Aortic Valve↗
PubMed2004

Tailored surgical therapy for acute native mitral valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: Mitral valve repair has been shown superior to valve replacement for the treatment of non-infectious valve disease. The criteria and results of valve repair for native valve endocarditis are still being defined. The study aim was to examine the short- and long-term results of mitral valve repair and replacement for acute infective endocarditis and to define criteria for the use of each technique. METHODS: A total of 53 consecutive patients who presented with acute native mitral valve infective endocarditis (diagnosed less than six weeks before surgery) between January 1992 and June 2002 was retrospectively analyzed. RESULTS: Twenty-one patients (40%) underwent mitral valve repair, and 32 (60%) underwent valve replacement. Operative mortality was 0% for the repair group and 13% (4/32) for the replacement group (p = 0.14). Median follow up was 4 years (range: 6-108 months). At five years follow up, a median ejection fraction (EF) of 60% and mitral regurgitation (MR) grade of 1/4 was observed, with an overall late survival of 85% (19/21), in the repair group, while the replacement group had a median EF of 55% and an overall late survival of 73% (p = 0.73). Recurrent endocarditis occurred in 2/21 (10%) in the repair group and 1/32 (3%) in the replacement group (p = 0.34). CONCLUSION: Mitral valve repair is a safe and effective technique to treat acute native mitral valve infective endocarditis with favorable short- and long-term morbidity and mortality. Patients with advanced endocarditis and annular destruction require valve replacement. Mitral valve repair should be performed when technically feasible.

Acute Disease↗
PubMed2003

Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping.

The use of near-infrared or infrared photons is a promising approach for biomedical imaging in living tissue. This technology often requires exogenous contrast agents with combinations of hydrodynamic diameter, absorption, quantum yield and stability that are not possible with conventional organic fluorophores. Here we show that the fluorescence emission of type II quantum dots can be tuned into the near infrared while preserving absorption cross-section, and that a polydentate phosphine coating renders them soluble, disperse and stable in serum. We then demonstrate that these quantum dots allow a major cancer surgery, sentinel lymph node mapping, to be performed in large animals under complete image guidance. Injection of only 400 pmol of near-infrared quantum dots permits sentinel lymph nodes 1 cm deep to be imaged easily in real time using excitation fluence rates of only 5 mW/cm(2). Taken together, the chemical, optical and in vivo data presented in this study demonstrate the potential of near-infrared quantum dots for biomedical imaging.

Animals↗
PubMed2003

Robotic mammary takedown and off-pump bypass surgery for single-vessel disease of the left anterior descending coronary artery.

Robotic takedown of the left internal mammary artery and direct off-pump anastomosis to the left anterior descending artery through small thoracotomy incisions can be done safely with minimal morbidity and is associated with decreased blood loss, decreased ventilatory requirements, less intensive care unit stay, and less overall length of stay. It should be considered as an alternative to percutaneous angioplasty and stenting for those with isolated left anterior descending artery disease.

Adult↗
PubMed2003

Hypothermic circulatory arrest for the surgical treatment of complicated adult coarctation of the aorta.

OBJECTIVES: This study was designed to evaluate the surgical treatment of recurrent coarctation by a new technique. BACKGROUND: Recurrent coarctation either from aneurysm or recurrent constriction is a difficult problem in the adult because of the possible interruption of important collateral circulation. METHODS: We reviewed four patients who underwent recurrent coarctation surgery with the use of deep hypothermic circulatory arrest (HCA). RESULTS: All four patients survived. Deep HCA facilitated precise surgical resection and there was no postoperative paraplegia, stroke, or myocardial infarction. CONCLUSIONS: Deep HCA and resection and grafting of the coarctation is indicated for complicated adult coarctations, particularly when the collateral circulation is in doubt.

Adult↗
PubMed2003

Metastatic carcinoid tumor of the heart.

Although carcinoid heart disease has been well described in the literature, metastatic implantation in the heart is rare. We describe a 79-year-old man with no previous history of cancer who presented with progressive dyspnea. He was found to have a septal implantation of a previously undiagnosed metastatic carcinoid tumor. He underwent successful resection with an uneventful postoperative course.

Aged↗
PubMed2003

Biological vs. mechanical aortic root replacement.

OBJECTIVES: Although age and co-existing coronary disease are major determining factors when deciding valve choice (mechanical vs. biological) in simple aortic valve replacement, no studies have documented selection criterion for biological (BIO) vs. mechanical (MECH) aortic root prosthesis. METHODS: Two hundred and twenty-one consecutive patients underwent elective aortic root replacement with either BIO (homograft, n=111, Freestyle, n=25) or MECH composite grafts (n=85). Median age in BIO was 53 years and in MECH 54 years (P=NS). Groups were similar in gender, NYHA class and ejection fraction (BIO, EF=59% vs. MECH, EF=55%), but the need for concomitant coronary artery bypass grafting (CABG) did differ between groups (MECH=35% vs. BIO=17%, P=0.003). Mean follow-up was 42+/-28 months for mortality and 39+/-28 months for morbidity. RESULTS: Full root replacement was performed in 213 patients (96%) and hemi-root in eight (4%). The most common underlying etiologies were annulo-aortic ectasia (n=82, 37%), calcified-degenerative (n=73, 33%) and bicuspid/congenital aortic valve disease (n=39, 18%). Operative mortality was 1.5% for BIO and 2.4% for MECH (P=0.5). By univariate analysis there was a trend towards greater 5-year survival in BIO (92.4% vs. 88.2%, P=0.068). By multivariate analysis, increasing age (HR=2.4, P=0.003), previous valve replacement (HR=4.7, P=0.024), concomitant CABG (HR=3.7, P=0.032), and perioperative stroke (HR=9.9, P=0.0005) were all independent predictors of late death. The 5-year freedom from valve-related complications was similar in both groups (BIO=93% vs. MECH=86%, P=0.5). CONCLUSIONS: Elective aortic root replacement is an exceedingly safe operation. At mean follow-up of 4 years, there is no meaningful difference in early or mid term valve-related results between BIO and MECH aortic root replacement. Continued evaluation for late valve-related complications in this cohort will be necessary to determine the advantages, if any, of one prosthesis over the other.

Adult↗
PubMed2003

Transcriptional profiling and growth kinetics of endothelium reveals differences between cells derived from porcine aorta versus aortic valve.

OBJECTIVE: Valvular tissue and aorta calcify at different rates when placed as fresh homografts or cryopreserved allografts. Furthermore, differences between valvular endothelial cells and aortic endothelial cells are not well appreciated. We established primary cultures of valve and aortic endothelial cells derived from swine and tested transcriptional and proliferative differences on various extracellular matrices. METHODS: Transcriptional profiling was performed on primary cultures of porcine valve and aortic endothelial cells. We extracted total RNA from both cell types and created cDNA libraries. We scored for 847 genes important in signal transduction pathways, and measured their expression on valve and aortic endothelial cells. To determine if there were functional differences between aortic and valvular cells, their growth rate was determined by cell counting on various extracellular matrices. RESULTS: Of 847 genes investigated, 69 (8.1%) were transcriptionally active on aortic endothelial cells and 89 (10.5%) on valve endothelial cells. Common to both cell types were 55 genes, which represents 79.7% (55/69) of activated genes on aortic endothelial cells and 61.8% (55/89) of those in valve endothelial cells. Remarkable features of the analysis included Ephrin ligand and receptor specificity for cell type, a potential fibroblast growth factor autocrine loop in both cell types, as well as upregulation of the platelet-derived growth factor receptor in valvular cells. Aortic endothelial cells were noteworthy of upregulation of vascular endothelial cell growth factor-B and vascular cell adhesion molecule. Proliferation analysis revealed that valve endothelial cells grew more rapidly (12-fold over control) than aortic endothelial cells (3-fold over control). Furthermore, valve endothelial cells proliferated most rapidly on gelatin or collagen, whereas aortic endothelial cells were most proliferative on lysine or laminin. CONCLUSIONS: Valve and aortic endothelial cells have different transcriptional and proliferative profiles. The knowledge of these differences may be an exploitable strategy in the future rational design of artificially engineered valve surfaces and in the study of the valve antigenicity, immunogenicity and structural failure.

Animals↗