Biomedical subjects

Mirko Doss

Publications and source records attributed to Mirko Doss.

17 recordsLinked to original sources

PubMed2005

Echocardiographic assessment in minimally invasive mitral valve surgery.

BACKGROUND: Due to limited exposure, removal of intracavitary air and visual assessment of cardiac function during minimally invasive procedures are not always possible. We analysed the utility of intraoperative transesophageal echocardiography (TEE) and postoperative transthoracic echocardiographic (TTE) in minimally invasive mitral valve (MV) procedures. MATERIAL/METHODS: We evaluated data from 163 consecutive patients undergoing isolated minimally invasive MV replacement (n=40) or repair (n=123) via small right anterolateral thoracotomy (121 complex mitral procedures). Cardioplegic arrest was achieved using either endoaortic (n=23) or transthoracic aortic clamp (n=140). In addition to preoperative TTE, TEE was used intraoperatively before and after cardiopulmonary bypass (CPB). Postoperative TTE was performed to monitor valve function at 3 and 12 months, and at 5-year follow-up. RESULTS: Pre-CPB TEE was useful to assess valve dysfunction and assist in placement of the arterial and venous cannulas. During CPB, placement and positioning of the endoclamp were guided effectively in all but 4 patients, in whom recurrent balloon migration necessitated secondary transthoracic aortic clamping. TEE detected one acute retrograde aortic dissection and one circumflex artery occlusion. After 18.7+/-10.6 months follow-up, all patients except three improved symptomatically and had consistently good valve function. CONCLUSIONS: Intraoperative TEE is essential for minimally invasive MV surgery, because it allows immediate control of valve function before and after surgery. It is useful to detect unexpected complications requiring immediate remedy. Postoperative echocardiographic results show that minimally invasive MV surgery is a good alternative to conventional surgery even in complex MV repairs.

Adolescent↗

PubMed2005

Aortic leaflet replacement with the new 3F stentless aortic bioprosthesis.

PURPOSE: Clinical trials with the new 3F stentless aortic bioprosthesis began October 2001, and as one of the first centers to implant this prosthesis in humans, we would like to present our experiences with this new device. DESCRIPTION: The 3F aortic bioprosthesis is a stentless biological heart valve fabricated from three equal leaflets of equine pericardium, assembled in a tubular shape, and implanted in the native aortic root to replace the patient's diseased aortic leaflets. Between January 2002 and August 2002, 24 3F aortic bioprostheses were implanted at our institution. Effective orifice area, mean gradients, and ejection fraction were evaluated by echocardiography at discharge and at 12-month follow-ups after surgery. EVALUATION: At 12-month follow-ups, the 3F bioprosthesis showed a good hemodynamic performance with a significant drop of mean gradients to 10.3 mm Hg, a mean effective orifice area of 1.7 cm2, and a mean ejection fraction of 61.5%. CONCLUSIONS: The clinical performance of the new 3F aortic bioprosthesis is comparable with regular stentless aortic valves. However its unique design facilitates implantation.

Adult↗

PubMed2005

Pericardial patch augmentation for reconstruction of incompetent bicuspid aortic valves.

PURPOSE: Reoperation rates after repair of bicuspid aortic valves are higher than for mitral valve reconstruction. Secondary changes and small coaptation surface render repair unreliable. Satisfactory results have been reported for patch augmentation for tricuspid aortic valves. We have applied this technique for the repair of bicuspid aortic valves. DESCRIPTION: Our technique retains the bicuspid morphology of the incompetent aortic valve. A strip of glutaraldehyde-fixed pericardium is sutured to the free edge of the fused leaflet. A large coaptation surface is created, and competence of the bicuspid valve is achieved. EVALUATION: Sixteen patients underwent reconstruction of their bicuspid aortic valves by pericardial patch augmentation. There were no intraoperative or postoperative deaths. The degree of aortic regurgitation was none to trivial for all patients at a mean follow-up of 3.1 +/- 3.4 months. Planimetric effective orifice areas ranged above 2 cm2. Mean aortic gradients were 8.2 +/- 4.8 mm Hg, and the mean height of coaptation surface was 14.7 +/- 2.1 mm. CONCLUSIONS: The pericardial patch augmentation technique increases coaptation surface, and thus provides reliable early competence of reconstructed bicuspid aortic valves.

Adult↗

PubMed2005

Emergency endovascular interventions for acute thoracic aortic rupture: four-year follow-up.

OBJECTIVE: High mortality and paraplegia rates associated with the surgical management of acute thoracic aortic ruptures limit its success. It was our objective to evaluate whether emergency endovascular interventions would improve the outcomes of these patients. METHODS: Sixty patients aged 28 to 83 years were admitted to our institution with an acute rupture of the thoracic aorta (27 ruptured aneurysms, 15 perforated type B dissections, 18 traumatic ruptures). Twenty-eight patients were treated surgically with cardiopulmonary bypass, and 32 patients were acutely treated with an endovascular stent graft. Medical records were reviewed for prehospital and emergency department data, operative findings, and outcomes. Patients were followed up at yearly intervals with high-resolution multidetector computed tomographic angiography. RESULTS: Perioperatively, there were 1 death (3.1%) among the 32 patients in the endovascular group and 5 deaths (17.8%) among the 28 patients in the surgical group. There were 4 late deaths in the endovascular group and 1 in the surgical group. There were 2 access failures in the endovascular group. There were 1 stroke in the endovascular group and 1 case of paraplegia in the surgical group. Three patients in the endovascular group had endovascular leaks develop that required reintervention. Two patients in the endovascular group had late thrombosis of the left subclavian artery. CONCLUSION: Despite encouraging early outcomes, midterm results suggest a trend toward increased reintervention and late complication rates in the endovascular group. Therefore continued surveillance of patients treated with stent grafts is necessary.

Aged↗

PubMed2005

Valve opening and closing dynamics after different aortic valve-sparing operations.

BACKGROUND AND AIM OF THE STUDY: Aortic valve resuspension for ascending aortic aneurysm repair is associated with removal of the sinus of Valsalva. This may cause changes in leaflet motion and thus impact on long-term durability. The opening and closing characteristics of the aortic valve leaflets after reimplantation were studied using a published technique and a modification to create a 'neosinus', and the results compared to those of an age-matched control group. METHODS: Between September 1995 and March 2002, 25 patients underwent normal aortic root reconstruction (group A), while in a further 21 patients the modified neosinus technique was used (group B). In both groups, the native valve was preserved and suspended inside a tubular prosthesis, with reimplantation of the coronary arteries. Transthoracic and transesophageal studies of aortic valve dynamics were performed intraoperatively, before hospital discharge, and at one year after surgery in all patients; the data were compared with those from a separate group of 25 matched control individuals (group C). RESULTS: The valve opening velocity was 61.3+/-20.1, 46.3+/-8 and 29.2+/-9.8 cm/s in groups A, B and C, respectively (group A versus B, p = 0.003; A versus C, p <0.0001; B versus C, p <0.0001). Closing velocity was increased to 57.5+/-23 and 43.8+/-7 cm/s in groups A and B, compared to 23.6+/-7 cm/s in group C (A versus B, p = 0.012; A versus C, p <0.0001; B versus C, p = 0.0002). In seven group A patients, the leaflets touched the prosthetic wall during systole. Slow systolic closing displacement (SCD) amounted to 7.3+/-6 % of maximal opening in group A and 12.6+/-5 % in group B (p = 0.05), compared to 21.1+/-8.3% in group C (group A versus group C, p <0.0001; B versus C, p = 0.002). CONCLUSION: Reimplantation of the natural aortic valve in a prosthetic graft causes abnormally high opening and closing speeds, with possibly increased stress. The study results showed lower valve opening and closure dynamics after the creation of a sinus bulge compared to the conventional reimplantation technique. However, mid-term clinical observations showed favorable valve competence for both types of repair. Further long-term follow up is necessary to prove whether more physiological leaflet dynamics lead to improved durability.

Adolescent↗

PubMed2004

Automatic connector devices for proximal anastomoses do not decrease embolic debris compared with conventional anastomoses in CABG.

OBJECTIVE: Emboli generated during cardiac surgery have been associated with aortic clamping and manipulation. Proximal anastomotic devices are thought to be less traumatic by eliminating partial clamping, potentially resulting in fewer adverse outcomes. Intra-aortic filtration has been shown to effectively capture particulate debris. We compared the amount of debris released using intra-aortic filtration and the clinical outcomes between conventionally handsewn and automated proximal anastomoses. METHODS: Seventy-seven patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass were enrolled in a prospective randomized study. Patients were assigned to the anastomotic device Group I (Symmetry Aortic Connector, n = 39) or the conventional handsewn anastomosis control Group II (n = 38). Proximal anastomoses were performed before cardiopulmonary bypass in both groups. Intra-aortic Filter 1 (EMBOL-X)was deployed prior to partial clamping or puncturing the aorta for device application and removed after the proximal anastomosis was completed. Prior to cross-clamp removal, a second filter was inserted (Filter 2). A core laboratory performed quantitative and histologic analyses of the debris captured. Clinical outcomes included adverse events, neurocognitive test scores, graft patency, and mortality. RESULTS: Preoperative variables and risk factors were not significantly different between Groups I and II (EuroSCORE 3.9+/-2.6 vs. 4.2+/-2.5). Filter analyses showed no significant difference between Groups I and II in Filter 1 or 2 for either surface area of particles or total number of particles (P> 0.005). There was a significant decrease between Filters 1 and 2 in both Groups for surface area of particles (Group I: 18.5+/-23.8 mm2 vs. 10.7+/-16.3 mm2, P = 0.017; Group II: 15.0+/-15.4 mm2 vs. 6.9+/-.6.5 mm2, P = 0.004), and for total number of particles in Group II (8.6+/-3.7 vs. 7.1+/-2.4, P = 0.023). No significant differences were observed between Group I (device) and Group II (control) outcomes for myocardial infarction, neurocognitive deficit, stroke, length of stay, graft occlusion, or mortality. CONCLUSIONS: The application of proximal aortic connectors without partial clamping does not reduce particulate emboli or affect clinical outcomes compared with conventional anastomoses. Cross-clamping during cardiopulmonary bypass produces less particulate debris than conventional or automated proximal anastomoses performed off-pump, suggesting a major source of emboli is the anastomotic process.

Adult↗

PubMed2003

Urgent thoracic aortal dissection and aneurysm: treatment with stent-graft implantation in an angiographic suite.

The aim of this study was to evaluate the feasibility of endoluminal stent-graft placement in an angiographic suite for the treatment of emergent type-B aortic dissections and ruptured thoracic aortal aneurysms. Twenty-six patients with either urgent type-B dissection (n=8) or aneurysms (n=18) of the descending thoracic aorta were chosen for stent-graft implantation. All patients received a multidetector-row CT angiography of the whole aorta and pelvic arteries prior to stent-graft implantation. All procedures were performed in a fully equipped digital subtraction angiography (DSA) suite under general anesthesia. In 20 patients Talent LPS tube grafts and in 4 patients an Excluder graft were used. Access was achieved via surgical cut-down in the left (n=7) or right (n=19) groin. Sealing was successful in 24 patients. The proximal covered portion of the stent graft was placed across the left subclavian artery in 2 patients. Procedural success was achieved in 23 of 24 patients. One patient required a second stent-graft placement before the aneurysm was sealed. One patient with an acute perforation of the descending aorta died due to cardiac failure prior to stent-graft implantation. In 1 patient stent-graft delivery failed due to severe calcification of both common iliac arteries. Endoluminal treatment of both urgent type-B aortic dissections and thoracic aortal aneurysms with stent graft is an attractive alternative treatment to surgical repair. The placement of stent grafts in an angiographic suite is a safe and feasible method with good clinical effectiveness and, so far, good clinical outcome.

Acute Disease↗

PubMed2003

Emergent endovascular stent grafting for perforated acute type B dissections and ruptured thoracic aortic aneurysms.

BACKGROUND: The purpose of our study was to demonstrate the effectiveness of endovascular stent grafts in the treatment of acutely ruptured thoracic aortic aneurysms and type B dissections as an alternative to the conventional surgical approach in an emergency setting. METHODS: From January 2001 to October 2001, we deployed 11 emergent endovascular stent grafts into the thoracic aorta. We treated seven ruptured aortic aneurysms and four acutely perforated type B dissections. Aortic rupture was confirmed preoperatively by spiral computed tomography. In all cases, hemothorax was present. The average interval from onset of symptoms to treatment was 28.5 hours. We used nine Talent and two Excluder stent grafts. RESULTS: Deployment of the stent grafts was successful in nine cases. There were two cases of access failure due to small caliber of iliac arteries, and 1 of these patients died shortly after the procedure was abandoned, At 12 months of follow-up, there were no cases of paraplegia, stent migration, or endoleaks. There was, however, one temporary renal failure, and 2 patients required mechanical ventilation for more than 48 hours. CONCLUSIONS: Our experiences with emergency endovascular stent grafting show that the procedure is technically feasible, with less morbidity and mortality than conventional open surgery, in high-risk patients.

Adult↗

PubMed2003

Surgical versus endovascular treatment of acute thoracic aortic rupture: a single-center experience.

BACKGROUND: Surgical management of acute thoracic aortic ruptures is controversial, especially in patients with preexisting comorbidities; associated mortality and paraplegia rates remain high. It was our objective to evaluate whether treating these patients acutely with endovascular stent grafts would improve their outcome. METHODS: From November 1999 to February 2002 a total of 54 patients, age 28 to 83 years, were admitted to our institution with an acute rupture of the thoracic aorta (24 ruptured aneurysms, 14 perforated type B dissections, 16 traumatic ruptures). Twenty-eight patients were managed surgically using cardiopulmonary bypass (group 1), and 26 patients were treated acutely with an endovascular stent graft (group 2). The resuscitation protocol and interval from onset of symptoms to treatment was comparable in both groups. Medical records were reviewed for prehospitalization and emergency department data, operative findings, and outcomes. RESULTS: There were 5 of 28 deaths (17.8%) in the surgical group and 1 of 26 deaths (3.8%) in the endovascular group. In the surgical group 1 of 28 patients (3.6%) exhibited paraplegia; there were no cases of paraplegia in the endovascular group. There were 4 of 28 cases (14.3%) of renal failure in group 1 and 1 of 26 (3.8%) in group 2. In group 1, 8 patients (28.6%) required mechanical ventilation for more than 48 hours; there were 2 of 26 patients (7.7%) in group 2 with this ventilatory requirement. Three patients required a repeat thoracotomy for hemorrhage in the surgical group. There were two access failures in the endovascular group. CONCLUSIONS: In the treatment of acute ruptures of the thoracic aorta, the immediate outcome of patients treated with endovascular stent grafts appears to be better than with management by conventional surgical repair.

Adult↗

PubMed2003

The clamshell approach for the treatment of extensive thoracic aortic disease.

OBJECTIVE: Management of extensive thoracic aortic disease may present an immense technical challenge. The choice of surgical access and subsequent exposure determines whether a single-stage or a 2-stage approach can be adopted. METHODS: Fifteen patients with extensive thoracic aortic disease underwent resection of the ascending aorta, the aortic arch, and varying segments of the descending aorta. Four patients had concomitant coronary artery bypass grafting and 3 patients had aortic valve reconstruction. All patients were treated with a single-stage approach via a bilateral anterior thoracosternotomy (clamshell incision). RESULTS: There was 1 hospital death (6.6%). Two patients required reoperation for bleeding (13.3%). Two patients needed mechanical ventilation for more than 48 hours. Three patients suffered a stroke (20%). Two patients (13.3%) had transient neurologic dysfunction. None of the patients had renal failure. There were no wound infections in this group. CONCLUSION: The single-stage approach, via a clamshell incision, is a safe and effective procedure for patients who require treatment of extensive thoracic aortic disease and concomitant cardiac lesions.

Aged↗

PubMed2003

Minimally invasive versus conventional aortic valve replacement: a prospective randomized trial.

BACKGROUND AND AIM OF THE STUDY: A prospective randomized study was performed to compare conventional with minimally invasive aortic valve replacement (AVR). METHODS: Forty consecutive patients scheduled for elective aortic valve surgery were prospectively randomized either to the conventional group (group A, complete median sternotomy) or minimally invasive group (group B, partial upper sternotomy). Intraoperative and postoperative clinical data, and markers of myocardial and cerebral protection were determined. Neuropsychological tests were carried out to quantify psychological disorders. RESULTS: Operative time and cardiopulmonary bypass time were slightly longer in group B, but not significantly so. No significant inter-group differences were found for postoperative pain scores and respiratory function. Chest tube drainage was significantly less in group B (495 +/- 165 versus 240 +/- 69 ml, p = 0.008). Creatine kinase (CK), CK-MB and troponin T levels were similar in both groups. Neither S-100B protein nor neuron-specific enolase levels differed significantly between groups at all sampling times. There were no strokes in the entire cohort. None of the neuropsychological tests yielded significant inter-group differences between conventional and minimally invasive surgery. CONCLUSION: The safety and reliability of AVR via a partial upper sternotomy is reported. Minimally invasive AVR can be performed with only slightly longer operative times, good cosmetic results and significantly less blood loss. A limited surgical access affected neither the patients' neurological outcome nor the efficacy of myocardial protection.

Aortic Valve Insufficiency↗

PubMed2003

Emergent endovascular interventions for contained rupture of thoracic aortic aneurysms.

BACKGROUND: The purpose of our study was to assess in an emergency setting the feasibility of endovascular stent graft treatment of contained ruptures of thoracic aortic aneurysms. METHODS: Seven patients with contained ruptures of thoracic aortic aneurysms from a series of 54 endovascular interventions were treated by the deployment of an aortic stent graft. In all cases, hemothorax was present. Acute deployment was performed with the patient under general anesthesia, and access was gained via the common femoral or iliac arteries. After a follow-up o f 12 months, the patients were evaluated by computed tomography. RESULTS: One patient died perioperatively. The procedure was technically successful in 5 patients. Perioperatively and at follow-up, there were no cases of paraplegia, stent graft migration, or endoleaks. There were, however, 2 cases of access failure, 1 case of temporary renal failure, and 2 patients who required prolonged mechanical ventilation. CONCLUSION: The acute treatment of contained ruptures of thoracic aortic aneurysms is feasible. This form of treatment seems to be a promising option in the treatment of these high-risk patients.

Aged↗

PubMed2003

Ultrafast computed tomography for quality control of automated proximal anastomoses.

BACKGROUND: The Symmetry aortic connector uses a nitinol implant to create proximal anastomoses with saphenous vein grafts. Multiple detector-row cardiac computed tomography (MDCT) is used as a noninvasive method of quality control at our institution. METHODS: In 50 elective coronary artery bypass grafting patients who participated in a randomized trial comparing automated with conventionally hand-sewn proximal anastomoses, MDC T was performed on postoperative day 5. Fifty-three automated Symmetry anastomoses were created in 34 patients (group 1). Twenty-five conventionally hand-sewn anastomoses created in 16 patients served as controls (group 2). Graft patency and the presence or absence of high-grade stenosis at the proximal anastomotic site were evaluated. RESULTS: In group 1, 2 (3.8%) of the grafts were found occluded at MDCT or coronary angiography, and no further relevant stenosis was observed. In group 2, at postoperative MDCT all grafts were found patent without significant narrowing of the proximal anastomotic site. CONCLUSIONS: The feasibility of proximal anastomoses using the Symmetry device has been reported. Patency control with invasive angiography has been performed by other groups. With MDCT, noninvasive evaluation of proximal anastomotic quality and graft patency is possible, even if nitinol is implanted.

Aged↗

PubMed2002

Biventricular pacing for weaning from extracorporeal circulation in heart failure.

Resynchronization of the intra- and interventricular conduction by biventricular pacing has been suggested in patients with end-stage heart failure. We present a case in which extracorporeal circulation could only be weaned after placement of an additional left ventricular pacing wire. Biventricular stimulation led to normal motion of the anterior wall and a previously bulging interventricular septum; this improved the hemodynamic situation significantly.

Aged↗

PubMed2002

The Heartflo device for distal coronary anastomoses: clinical experiences in 60 patients.

BACKGROUND: The Heartflo anastomotic device automates the suturing process with simultaneous delivery of 10 standard polypropylene sutures through the graft and the coronary vessel wall to construct the anastomosis. We performed clinical testing in 60 patients undergoing coronary artery bypass grafting. METHODS: One automated distal coronary anastomosis was initially placed in each patient, the other anastomoses were created with standard running sutures. After a "flat foot"-shaped prototype was deployed in 30 patients (group I), the design of the foot was modified and deployment of the new device performed in the next 30 patients (group II). RESULTS: In group I, automated anastomoses were completed in 16 patients (53%) using 1.7 +/- 1 additional stitches. In 26 group II patients (86%), a hemostatic anastomosis using 1.2 +/- 1 additional stitches was achieved. Anastomoses were completed in 19.0 +/- 3 minutes in group I and in 15.6 +/- 2 minutes in group II. CONCLUSIONS: We have shown the feasability of coronary anastomoses using the Heartflo device. The modified version improved tissue capture, resulting in a higher rate of completed anastomoses. Because anastomotic time is still prolonged, an easier suture management is mandatory in the next developmental step.

Aged↗

PubMed2002

Vacuum-assisted suction drainage versus conventional treatment in the management of poststernotomy osteomyelitis.

OBJECTIVE: The purpose of our study was to compare vacuum-assisted suction drainage (VASD) to conventional wound management, in the treatment of poststernotomy osteomyelitis (SOM). METHODS: We included a total of 42 patients that developed poststernotomy osteomyelitis and required open wound management, between 1998 and 2000, in this study. Twenty of these patients were treated by VASD and the other 22 by conventional wound management. The patients were well comparable with regards to age, presenting postoperative day, infecting organism and risk factors for osteomyelitis. This was a retrospective study. RESULTS: The patients treated by VASD had a significantly reduced treatment duration (mean 17.2+/-5.8 vs. 22.9+/-10.8 days, P=0.009) and total hospital stay (mean 27.2+/-6.5 vs. 33.0+/-11.0 days, P=0.03). Perioperative mortality was similar, with one early death in each group. CONCLUSION: We conclude from our experience in the treatment of 42 patients with poststernotomy osteomyelitis that VASD shortened wound healing and hospital stay and thus proved to be an excellent alternative to conventional open management of these wounds.

Aged↗

PubMed2002

Emergency endovascular interventions for ruptured thoracic and abdominal aortic aneurysms.

BACKGROUND: The purpose of our study was to show the effectiveness of endovascular stent grafts in the treatment of acutely ruptured abdominal and thoracic aortic aneurysms as an alternative to the conventional surgical approach in an emergency setting. METHODS: From October 1996 to October 1998 we deployed 9 emergent endovascular stent grafts--6 in the abdominal aorta and 3 in the thoracic aorta. Aortic rupture was confirmed before surgery with spiral-computed tomographic scan. The average interval from onset of symptoms to treatment was 4.5 hours. We used commercially manufactured stent grafts: 4 Corvita (Corvita Inc/Schneider Corp/Boston Scientific Corp, Natick, Mass), 3 Talent (World Medical Inc, Surise, Fla/Medtronic, Sunnyvale, Calif), and 2 Vanguard (Boston Scientific Corp, Natick, Mass). RESULTS: Deployment of the stent grafts was successful in all cases. Two patients died in the follow-up period (120 months) from myocardial infarction. No cases were seen of paraplegia or stent migration. However, 2 endoleaks, 1 in-stent stenosis, 1 temporary renal failure, and 1 brief episode of myocardial ischemia occurred. CONCLUSION: Our experiences with emergency endovascular stent grafting show that the procedure is technically feasible, with less morbidity and mortality than conventional open surgery, in selected patients.

Adult↗