Decalcification of the Mitral Annulus: Surgical Experience in 81 Patients.

OBJECTIVE: Mitral valve surgery in the presence of extensive calcification of the mitral annulus is a technical challenge and increases perioperative risk. This study reviews our experience with decalcification of the mitral annulus in patients undergoing mitral valve reconstruction or replacement.

METHODS: From 1995 to 2003, 81 patients (mean age 64 +/- 13 years, 30 male, 51 female) with extensive calcification of the mitral annulus underwent mitral valve repair (n = 42) or replacement (biological n = 20, mechanical n = 19). The mean follow-up was 24 months. Patients presented with a mean EuroSCORE of 7. Concomitant surgical procedures were performed in 62 %. Patient outcomes were retrospectively assessed.

RESULTS: Perioperative survival was 97.5 % (n = 79) and hospital survival was 91.3 % (n = 74). Two-year survival was 88.9 %. Eight patients needed reexploration due to bleeding and five patients required prolonged mechanical ventilation. No perioperative stroke was observed. Freedom from reoperation was 90.2 % (n = 73). Early reoperation for recurrent incompetence was necessary in 3 patients and late reoperation in 5 patients.

CONCLUSIONS: Despite the elevated perioperative risk and the high risk of reoperation with this procedure, decalcification of the annulus and repair/replacement of the mitral valve could be performed with good clinical results.

Author(s): M Dietrich , M Doss , T Aybek , S Martens , M Scherer , G Wimmer-Greinecker, A Moritz

in: Thorac Cardiovasc Surg. 2006 Oct ;54 (7):464-467 17089313

Stentless bioprostheses improve postoperative coronary flow more than stented prostheses after valve replacement for aortic stenosis.

OBJECTIVE: In some randomized studies, stentless aortic valves have demonstrated hemodynamic advantages in comparison with stented prostheses. The effect of more physiologic flow dynamics on coronary artery flow has not been investigated yet. This study compares coronary perfusion after aortic valve replacement with stented or stentless porcine bioprostheses in a prospective randomized study.

METHODS: A total of 24 patients (73 +/- 6 years) referred for treatment of aortic stenosis were randomized to aortic valve replacement with stented (Medtronic Mosaic; (Medtronic Inc, Minneapolis, Minn) or stentless (Medtronic Freestyle; Medtronic Inc) prostheses. Coronary flow was measured by means of magnetic resonance imaging preoperatively, 5 days after the operation, and 6 months postoperatively, then with evaluation of coronary flow reserve. Echocardiography was performed to quantify transvalvular gradients and left ventricular mass regression.

RESULTS: Coronary flow increased in both groups significantly.

Author(s): Farhad Bakhtiary, Mirko Schiemann, Omer Dzemali, Thomas Wittlinger, Mirko Doss, Hans Ackermann, Anton Moritz, Peter Kleine

in: J Thorac Cardiovasc Surg. 2006 Apr ;131 (4):883-8 16580448

Emergency endovascular interventions for acute thoracic aortic rupture: 4 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.

Author(s): Doss M, Wood JP, Balzer J, Martens S, Wimmer-Greinecker G, Moritz A.
in: Journal of Thoracic and Cardiovascular Surgery, 2005 Mar;129(3):645-51.

Read at the Thirtieth Annual Meeting of The Western Thoracic Surgical Association, Maui, Hawaii, June 23-26, 2004.

PMID: 15746750 [PubMed - indexed for MEDLINE]

Improved cerebral protection through replacement of residual intracavital air by carbon dioxide: a porcine model using diffusion-weighted magnetic resonance imaging.

BACKGROUND: Major risk of central or peripheral organ damage is attributed to air embolism from incompletely de-aired cardiac chambers after cardiac operations. Replacement of air by carbon dioxide insufflation into the thoracic cavity is widely used. Diffusion-weighted magnetic resonance imaging of the brain detects ischemia within minutes after onset. The reversibility of ischemia in cerebral tissue after massive gaseous emboli has not yet been described.

METHODS: After selective catheterization of a common carotid artery in 15 pigs, boli of 1 mL/kg body weight of air (n = 5) or carbon dioxide (n = 5, “low dose”) were applied. Five pigs received 2 mL/kg body weight of carbon dioxide (“high dose”). Diffusion-weighted magnetic resonance imaging of the brain was performed 2, 5, 10, 15, and 25 minutes after embolization.

RESULTS: All animals of the “air” group showed important circulatory reactions leading to death of 2 animals. In the whole group, diffusion-weighted magnetic resonance imaging revealed irreversible hyperintense signals in both hemispheres. In the low-dose group, no change in signal intensity was observed in 2 pigs, and 3 others showed reversible changes in signal intensity, without important circulatory reactions. In 3 animals of the high-dose group, hyperintense signals were reversible, but 2 others presented with bilateral, irreversible signals in diffusion-weighted magnetic resonance imaging, accompanied by minor circulatory reactions.

CONCLUSION: In contrast to the dramatic effect of air emboli, identical quantities of carbon dioxide injected into cerebral arteries of the pigs were not associated with major clinical symptoms. The early reversibility of ischemic reactions visualized in diffusion-weighted magnetic resonance imaging encourages the use of carbon dioxide insufflation as a protective method in cardiac surgery.

Author(s): Martens S, Theisen A, Balzer JO, Dietrich M, Graubitz K, Scherer M, Schmitz C,
Doss M, Moritz A.

in: J Thorac Cardiovasc Surg. 2004 Jan;127(1):51-6.

PMID: 14752412 [PubMed - indexed for MEDLINE]

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.

Author(s): Doss M, Woehleke T, Wood JP, Martens S, Greinecker GW, Moritz A.

in: J Thorac Cardiovasc Surg. 2003 Sep;126(3):814-7.

PMID: 14502158 [PubMed - indexed for MEDLINE]

Optimal carbon dioxide application for organ protection in cardiac surgery.

BACKGROUND: Cardiac surgery is associated with an important risk of central or peripheral organ damage, attributed in part to air embolism from incompletely deaired cardiac chambers. Insufflation of carbon dioxide into the thoracic cavity is widely used for organ protection in cardiac surgery.

METHODS: In patients operated on through a sternotomy, the gas was insufflated through a standard cardioplegia line (group I, n = 10) or a Jackson-Pratt drain (group II, n = 10), with flow rates of 2, 4, and 6 L/min. In patients undergoing mitral valve surgery through a right anterolateral minithoracotomy, application through a gas port (group III, n = 10) was compared with application through a Veress needle (group IV, n = 10). In groups I and IV measurements were repeated with a gauze sponge to divert the gas stream.

RESULTS: At a flow of 2 L/min, carbon dioxide levels in the thoracic cavity reached 52% +/- 30% in group I and increased to 81% +/- 27% when a gauze sponge was used. In group II a level of 91% +/- 5% was achieved. In minimally invasive procedures carbon dioxide levels reached 92% +/- 6% in group III and 60% +/- 25% in group IV without a gauze sponge and 97% +/- 2% in group IV with a gauze sponge. Increasing flow rates from 2 to 6 L/min decreased carbon dioxide levels in the thoracic cavity. Arterial blood gas analysis did not reveal critical levels of partial pressure of carbon dioxide at any time.

CONCLUSIONS: For optimized carbon dioxide concentrations during cardiac procedures, jet effects in the thoracic cavity have to be avoided. The highest levels were achieved with infusion lines covered by a gauze sponge or a perforated drain for conventional operations and a sponge-covered Veress needle or a gas port for minimally invasive approaches.

Author(s): Martens S, Dietrich M, Doss M, Wimmer-Greinecker G, Moritz A.
in: The Journal of Thoracic and Cardiovascular Surgery, 2002 Aug;124(2):387-91.

PMID: 12167800 [PubMed - indexed for MEDLINE]