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Diazaphospholenes are widely used as hydride transfer catalysts, however their use in radical reactions is a recently emerging area. Here, we show prior stoichiometric radical cyclizations of aryl iodides mediated by diazaphospholene hydrides are made catalytic by the combination of phenylsilane and alkali metal salts to regenerate the diazaphospholene hydride. The scope was expanded to include aryl bromides, which benefit from visible light irradiation. Twenty one substrates underwent cyclization, including a dearomative cyclization. Extension to six intermolecular radical hydroarylations with arenes, thiophenes, and a pyridine was also accomplished.
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Catenation is common for the light main-group elements whereas it is rare for the heavy elements. Herein, we report the first example of a neutral molecule containing a Bi4 chain. It is prepared in a one-step reaction between bismuth trichloride and bis(diisopropylphosphino)amine in methanol suspension. The same reaction carried out in dichloromethane gives quite different products. All products have been characterized spectroscopically and using single-crystal X-ray analysis.
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Background: This study of radiation exposure (RE) to physicians performing structural heart procedures evaluated the efficacy of a novel comprehensive radiation shield compared to those of traditional shielding methods. A novel comprehensive shielding system (Protego, Image Diagnostics Inc) has been documented to provide superior RE protection during coronary procedures compared to that provided by a standard "drop down" shield. The purpose of this study was to assess the efficacy of this shield in transcatheter aortic valve replacement (TAVR) procedures, which are associated with disproportionate RE to operators. Methods: This single-center, 2-group cohort, observational analysis compared RE to the primary physician operator performing TAVR using the Protego shield (n = 25) with that using a standard drop-down shield with personal leaded apparel (n = 25). RE was measured at both thyroid and waist levels with a real-time dosimetry system (RaySafe i3, RaySafe) and was calculated on a mean per case basis. Data were collected on additional procedural parameters, including access site(s) for device implantation, per case fluoroscopy time, air kerma, and patient factors, including body mass index. Between-group comparisons were conducted to evaluate RE by group and measurement sites. Results: The Protego system reduced operator RE by 99% compared to that using standard protection. RE was significantly lower at both the thyroid level (0.08 ± 0.27 vs 79.2 ± 62.4 µSv; P < .001) and the waist level (0.70 ± 1.50 vs 162.0 ± 91.0 µSv, P < .001). "Zero" total RE was documented by RaySafe in 60% (n = 15) of TAVR cases using Protego. In contrast, standard protection did not achieve zero exposure in a single case. Conclusions: The Protego shield system provides superior operator RE protection during TAVR procedures. This shield allows operators to work without the need for personal lead aprons and has potential to reduce catheterization laboratory occupational health hazards.
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Background: The catheterization laboratory predisposes to occupational health hazards. Chronic radiation exposure (RE) direct injuries include a predilection to cataracts and concerns for cancers. Indirectly adverse effects underly the prevalence of orthopedic maladies in interventionists, linked to the burden of mandatory protective lead aprons. A novel comprehensive shielding system (Protego, Image Diagnostics Inc) has been validated in early studies to provide excellent radiation protection. The system is designed to reduce operator RE sufficient to eliminate the need for personal lead aprons. Recent system refinements offer potentially even greater degrees of protection. This clinical study evaluated the efficacy of this system. Methods: This single-center 2-group cohort study compared physician operator RE utilizing the latest iteration of the Protego shield (n = 25 cases) or standard protection (personal leaded apparel and drop-down shield, n = 25 cases) during routine cardiac catheterization procedures. RE at both thyroid and waist levels were measured with a real-time dosimetry system (Raysafe) and calculated on a mean per case basis at both thyroid and waist levels. Additional parameters collected included procedure type, access site, per case fluoroscopy time, and patient factors including body mass index. Between-group comparisons were conducted to evaluate RE by group and measurement sites. Results: Protection with Protego was superior to standard methods. Protego showed markedly lower RE at both the thyroid level (0.36 ± 0.86 vs 58.5 ± 50.2 µSv; P < .001) and the waist level (0.84 ± 2.99 vs 121.4 ± 171.2 µSv; P < .001. "Zero" total RE was documented in 68% (n = 17) of Protego cases; in contrast, standard protection did not achieve "zero" exposure in a single case. Conclusions: The Protego shield system provides excellent RE protection to the physician operator, achieving "zero" RE in two-thirds of cases. RE was superior to standard protection methods. The magnitude of protection achieves state regulatory standards sufficient to allow operators to perform procedures without orthopedically burdensome lead aprons. This shield system has the potential to reduce occupational health hazards.
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BACKGROUND: Treatment of mitral regurgitation (MR) in the setting of severe mitral annular calcification (MAC) is challenging due to the high risk for fatal atrioventricular groove disruption and significant paravalvular leak. OBJECTIVES: The objective of this study was to evaluate the potential for transcatheter mitral valve replacement in patients with severe MAC using an anatomically designed mitral prosthesis. METHODS: Nine patients (77 ± 6 years of age; 5 men) were treated with the valve, using transapical delivery performed under general anesthesia and with guidance from transesophageal echocardiography and fluoroscopy. RESULTS: Device implantation was successful with relief of MR in all 9 patients. There were no procedural deaths. In 1 patient, left ventricular outflow tract obstruction occurred due to malrotation of the prosthesis, and successful alcohol septal ablation was performed. During a median follow-up of 12 months (range 1 to 28 months), there was 1 cardiac death, 1 noncardiac death, no other mortality, and no prosthetic dysfunction, and MR remained absent in all treated patients. Rehospitalization for heart failure occurred in 2 patients who did not die subsequently. Clinical improvement with mild or no symptoms occurred in all patients alive at the end of follow-up. CONCLUSIONS: Transcatheter mitral valve replacement in severe mitral annular calcification with a dedicated prosthesis is feasible and can result in MR relief with symptom improvement. Further evaluation of this approach for these high-risk patients is warranted.
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Calcinose/cirurgia , Cateterismo Cardíaco , Doenças das Valvas Cardíacas/cirurgia , Implante de Prótese de Valva Cardíaca/métodos , Valva Mitral/cirurgia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Índice de Gravidade de DoençaRESUMO
Heparin-induced antibodies create vexing problems during cardiac surgery. Although alternative medications have been used for intraoperative anticoagulation, the results have been sufficiently variable that no one medication is recommended. In our case, due to the poor reversibility of the antithrombin agents, argatroban was chosen as a heparin substitute due to its short half-life and its anticoagulation assessment using the activated clotting time (ACT). Unfortunately, our experience was that argatroban does not provide adequate anticoagulation during off-pump coronary bypass surgery, even when the ACT is maintained at more than 380 sec.
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Angina Instável/cirurgia , Anticoagulantes/efeitos adversos , Ponte Cardiopulmonar , Ponte de Artéria Coronária , Reestenose Coronária/cirurgia , Ácidos Pipecólicos/efeitos adversos , Idoso , Anticorpos/sangue , Anticoagulantes/uso terapêutico , Arginina/análogos & derivados , Relação Dose-Resposta a Droga , Oclusão de Enxerto Vascular/etiologia , Heparina/efeitos adversos , Heparina/imunologia , Heparina/uso terapêutico , Humanos , Masculino , Revascularização Miocárdica , Tempo de Tromboplastina Parcial , Ácidos Pipecólicos/uso terapêutico , Reoperação , Stents , Sulfonamidas , Falha de TratamentoRESUMO
BACKGROUND: Stentless porcine aortic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation, and perhaps improved durability. METHODS: One hundred four patients were operated on from September 17, 1992, to October 31, 1997, as part of a multicenter worldwide investigation of the Medtronic Freestyle stentless porcine bioprosthesis. All patients received a total aortic root replacement. The patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography. RESULTS: Operative mortality was 3.9%. No patient experienced structural valve deterioration, nonstructural deterioration, perivalvular leak, or unacceptable hemodynamic performance. At 8 years, survival was 59.8%. Freedom from thromboembolic complications was 83.3%. Freedom from postoperative endocarditis was 96.9%. Freedom from reoperation was 100%. Mean systolic gradients did not change over the time period studied. They were 6.4 +/- 3.8 mm Hg at 1 year and 6.7 +/- 2.6 mm Hg at 8 years. Correspondingly, effective orifice area was 1.9 +/- 0.7 cm2 at 1 year and 1.8 +/- 0.8 cm2 at 8 years. The incidence of any aortic insufficiency also did not change over the length of follow-up. At 1 year, 98% of patients had no or trivial aortic insufficiency and 2% had mild aortic insufficiency. At 8 years, 100% of patients evaluated were free of any aortic insufficiency. CONCLUSIONS: The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root or aortic valve for aortic valve and aortic root pathology. Total root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Results up to 8 years show excellent survival and no signs of degeneration. Further follow-up is still needed to determine valve durability.
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Valva Aórtica , Bioprótese , Próteses Valvulares Cardíacas , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese , Suínos , Fatores de TempoAssuntos
Insuficiência da Valva Aórtica/terapia , Valva Aórtica , Cateterismo Cardíaco/efeitos adversos , Cateterismo Cardíaco/instrumentação , Estenose Coronária/etiologia , Implante de Prótese de Valva Cardíaca/efeitos adversos , Implante de Prótese de Valva Cardíaca/instrumentação , Próteses Valvulares Cardíacas , Falha de Prótese , Idoso de 80 Anos ou mais , Angioplastia Coronária com Balão/instrumentação , Valva Aórtica/fisiopatologia , Insuficiência da Valva Aórtica/diagnóstico , Insuficiência da Valva Aórtica/etiologia , Insuficiência da Valva Aórtica/fisiopatologia , Aortografia , Cateterismo Cardíaco/métodos , Angiografia Coronária , Estenose Coronária/diagnóstico , Estenose Coronária/fisiopatologia , Estenose Coronária/terapia , Stents Farmacológicos , Ecocardiografia Transesofagiana , Feminino , Implante de Prótese de Valva Cardíaca/métodos , Humanos , Desenho de Prótese , Índice de Gravidade de Doença , Resultado do Tratamento , Ultrassonografia de IntervençãoRESUMO
BACKGROUND: Mitral valve repair improves survival and quality of life in patients with ischemic mitral regurgitation (MR). Although many repair methods exist for this condition, the ideal approach remains unknown. The purpose of this study is to describe a simple technique for repair of ischemic MR that addresses the pathophysiology of tethered leaflets and to report its early results. METHODS: The technique consists of pericardial patch enlargement of the anterior mitral leaflet and placement of a flexible annuloplasty band. Candidates for the repair had ischemic cardiomyopathy and echocardiographic evidence of moderate or severe Carpentier type IIIb MR. Patients were followed with serial echocardiography. RESULTS: Between January 2002 and November 2003, 25 adult patients underwent anterior leaflet augmentation for ischemic MR. Mean age was 64.8 +/- 10.6 years, and mean left ventricular ejection fraction was 0.36 +/- 0.14. Preoperative MR by transesophageal echocardiography was severe in 84% of patients and moderate in 16%. Annuloplasty band sizes were 27 mm to 31 mm (mean, 28.4 +/- 1.1 mm). Concomitant coronary artery bypass grafting was performed in all patients. Transesophageal echocardiography immediately after repair revealed MR to be none or trace in 80% of patients and mild in 20%. No intraoperative conversion to valve replacement was performed. In follow-up, 2 patients have experienced moderate MR and are being treated medically, and no patients have mitral stenosis. At 2 years, actuarial freedom from moderate or greater MR is 81%. CONCLUSIONS: For patients with ischemic MR, anterior leaflet augmentation is a simple and reproducible method of valve repair that addresses the pathophysiology of tethered leaflets. Early results in a small number of patients have been encouraging.
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Bioprótese , Insuficiência da Valva Mitral/cirurgia , Isquemia Miocárdica/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Ponte Cardiopulmonar , Bovinos , Ecocardiografia Transesofagiana , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/etiologia , Insuficiência da Valva Mitral/fisiopatologia , Pericárdio , Resultado do Tratamento , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/etiologiaRESUMO
Esophageal injury is a rare complication of intraoperative transesophageal echocardiography (TEE) associated with cardiac surgery. We report two cases of delayed presentation (2 and 6 days after surgery) of esophageal injury that were likely due to TEE. The differential diagnosis of postoperative pleural effusion or anemia must include esophageal injury from TEE, even 6 days after the procedure.