Serum cardiac troponin I concentration in dogs with ehrlichiosis.

BACKGROUND: Ehrlichiosis is a multisystemic disease with the potential to cause cardiomyocyte injury in naturally infected dogs. HYPOTHESIS: Myocardial injury occurs in dogs infected with Ehrlichia canis. ANIMALS: One-hundred and ninety-four dogs from Brazil with clinical and laboratory abnormalities indicative of ehrlichiosis. Sixteen healthy dogs served as controls. METHODS: Electrocardiogram, echocardiogram, noninvasive blood pressure measurement, and serum cardiac troponin I (cTnI) concentrations were evaluated. Serologic assays and PCR determined the exposure and infection status for E. canis, Anaplasma spp., Babesia canis vogeli, Bartonella spp., Borrelia burgdorferi, Dirofilaria immitis, Ehrlichia chaffeensis, Ehrlichia ewingii, Leishmania chagasi, and spotted-fever group Rickettsia. Dogs were assigned to groups according to PCR status: E. canis infected, infected with other vector-borne organisms, sick dogs lacking PCR evidence for infection, and healthy controls. RESULTS: E. canis-infected dogs had higher serum cTnI concentrations than controls (median: 0.04 ng/dL; range 0.04-9.12 ng/dL; control median: 0.04 ng/dL; range: 0.04-0.10 ng/dL; P= .012), and acute E. canis infection was associated with myocardial injury (odds ratio [OR]: 2.67, confidence interval [CI] 95%: 1.12-6.40, P= .027). Severity of anemia was correlated with increased risk of cardiomyocyte damage (r= 0.84, P< .001). Dogs with clinical signs of systemic inflammatory response syndrome (SIRS) were at higher risk for myocardial injury than were other sick dogs (OR: 2.55, CI 95%: 1.31-4.95, P= .005). CONCLUSIONS AND CLINICAL IMPORTANCE: Acute infection with E. canis is a risk factor for myocardial injury in naturally infected Brazilian dogs. Severity of anemia and SIRS might contribute to the pathophysiology of myocardial damage.

Calcium gluconate and sodium succinate for therapy of sodium fluoroacetate experimental intoxication in cats: clinical and electrocardiographic evaluation.

Sodium fluoroacetate (SFAC) or Compound 1080 is a potent rodenticide, largely used after 1946 for rodent and home pest control. The toxic effects of SFAC are caused by fluorocitrate action, a toxic metabolite, which has a competitive action with aconitase enzyme, leading to citrate accumulation and resulting in interference in energy production by Krebs cycle blockade. In the present study, domestic cats were intoxicated with oral doses of fluoroacetate (0.45 mg/kg). The intoxicated animals presented emesis, diarrhea with abdominal pain posture and an abdominal palpation, tachypnea, bilateral midriasis, hypothermia, hyperexcitability and convulsions. Blood gas analysis indicated decreased pH and bicarbonate levels. Serum ionized calcium was also decreased. ECG showed non-specific changes in ventricular repolarization and ventricular arrhythmias. The survival rate was 75% in the treated group with calcium gluconate and sodium succinate and 37.5% in the nontreated group.

Utility of transesophageal echocardiography during port-access minimally invasive cardiac surgery.

In this study, we sought to determine the use of transesophageal echocardiography (TEE) as the primary imaging technique to assist in the placement of endovascular catheters during minimally invasive, port-access cardiac surgery. The recent development of endovascular catheters that are placed via the femoral artery and vein has enabled patients to be placed on cardiopulmonary bypass without the need for direct visualization of the heart or great vessels via sternotomy. This has allowed cardiac surgery to be performed through smaller thoracotomy incisions. Placement of these catheters has previously been performed with fluoroscopic guidance, which has major imaging limitations. Thirty-six patients underwent port-access cardiac surgery at our institution during the study period. All patients underwent intraoperative TEE. We used TEE to visualize the coronary sinus os, right atrium and superior vena cava, and thoracic aorta to assist with placement of the coronary sinus catheter, venous cannula, and endoaortic clamp. Twenty patients underwent mitral valve surgery, 14 patients coronary artery bypass grafting, 1 patient aortic valve replacement, and 1 patient repair of an atrial septal defect by the port-access approach. TEE was able to adequately visualize the cardiac structures and assist in the placement of the endovascular catheters in all patients. Fluoroscopy was only helpful as an aid to TEE for placement of the coronary sinus catheter. TEE is an excellent imaging modality for the proper placement of these new endovascular catheters, obviating the need for fluoroscopy, except to be on standby and for placement of the coronary sinus catheter.

Single and multivessel port-access coronary artery bypass grafting with cardioplegic arrest: technique and reproducibility.

OBJECTIVES: Although minimally invasive coronary artery bypass grafting is now feasible, using this technique to perform anastomoses on the beating or fibrillating heart may yield poorer graft patency than the standard open techniques that use cardioplegic arrest. This study tested the feasibility and anastomotic reproducibility of minimally invasive coronary bypass using newly developed port-access coronary artery bypass technology (Heartport, Inc., Redwood City, Calif.), which allows endovascular cardiopulmonary bypass, cardiac venting, aortic occlusion, and cardioplegic arrest for internal thoracic artery-coronary artery anastomoses. METHODS: Nineteen dogs had thoracoscopic takedown of either single (n = 14) or bilateral (n = 5) internal thoracic arteries followed by minimally invasive coronary bypass with cardioplegic arrest, done by means of the port-access system. The anastomotic technique was modified after the fourth animal by switching from a microscope to a 2.5 cm oval port and performing a conventional anastomosis with operative loupes. The adequacy of delivery of cardioplegic solution, ventricular decompression, and anastomotic patency was assessed. RESULTS: The crossclamp and bypass times were 50 +/- 15 minutes and 87 +/- 28 minutes (mean +/- standard deviation), respectively. The mean myocardial temperature after cardioplegia was 17 degrees +/- 1 degree C and the aortic pressure (-3 +/- 9 mm Hg) and pulmonary artery pressure (4 +/- 1 mm Hg) were low throughout the procedure. All animals were weaned from bypass without inotropic agents. Angiograms and autopsies demonstrated successful thoracic artery takedown and anastomotic patency in 18 of 19 animals, with 100% anastomotic patency after the technique had been modified after the fourth animal. CONCLUSION: This study describes a reproducible technique for minimally invasive coronary bypass that allows myocardial protection, anastomotic precision, and predictable thoracic artery graft patency. Clinical trials are indicated.

Minimally invasive mitral valve replacement: port-access technique, feasibility, and myocardial functional preservation.

OBJECTIVE: This experiment examined the feasibility of minimally invasive port-access mitral valve replacement via a 2.5 cm incision. METHODS: The study evaluated valvular performance and myocardial functional recovery in six mongrel dogs after port-access mitral valve replacement with a St. Jude Medical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). Femoro-femoral cardiopulmonary bypass and a balloon catheter system for myocardial protection with cardioplegic arrest (Heartport, Inc., Redwood City, Calif.) were used. The mitral valve was replaced through a 2.5 cm port in the left side of the chest, and the animals were weaned from bypass. Cardiac function was measured before and at 30 and 60 minutes after bypass. Left ventricular pressure and electrical conductance volume were used to calculate changes in load-independent indexes of ventricular function. RESULTS: Each procedure was successfully completed. Recovery of left ventricular function was excellent at 30 and 60 minutes after bypass compared with the prebypass values for elastance (30 minutes = 4.04 +/- 0.97 and 60 minutes = 4.27 +/- 0.57 vs prebypass = 4.45 +/- 0.96; p = 0.51) and for preload recruitable stroke work (30 minutes = 76.23 +/- 4.80 and 60 minutes = 71.21 +/- 2.99 vs prebypass = 71.23 +/- 3.75; p = 0.45). Preload recruitable work area remained at 96% and 85% of baseline at 30 and 60 minutes (p = not significant). In addition, transesophageal echocardiography demonstrated normal prosthetic valve function, as well as normal regional and global ventricular wall motion. Autopsy revealed secure annular-sewing apposition and normal leaflet motion. CONCLUSIONS: These results suggest that minimally invasive mitral valve replacement using percutaneous cardiopulmonary bypass with cardioplegic arrest is technically reproducible, achieves normal valve placement, and results in complete cardiac functional recovery. Minimally invasive mitral valve replacement is now feasible, and clinical trials are indicated.

Minimally invasive cardiopulmonary bypass with cardioplegic arrest: a closed chest technique with equivalent myocardial protection.

Thoracoscopic cardiac surgery is presently under intense investigation. This study examined the feasibility and efficacy of closed chest cardiopulmonary bypass and cardioplegic arrest in comparison with standard open chest methods in a dog model. The minimally invasive closed chest group (n = 6) underwent percutaneous cardiopulmonary bypass and cardiac venting, as well as antegrade cardioplegic arrest through use of a specially designed percutaneous endovascular aortic occluder and cardioplegic solution delivery system. The control group (n = 6) underwent standard sternotomy and conventional open chest cardiopulmonary bypass, aortic crossclamping, and antegrade cardioplegia. Ischemic arrest time was 1 hour in each group. Ventricular pressures and sonomicrometer segment lengths were recorded before bypass and at 30 and 60 minutes after bypass. Left ventricular function did not differ significantly between the two groups, as demonstrated by measurements of elastance and end-diastolic stroke work. Also, the preload recruitable work area was 69% and 60% of baseline at 30 and 60 minutes after bypass in the minimally invasive group versus 65% and 62% in the conventional control group (p = not significant); the stroke work end-diastolic length relationship was 78% and 71% of baseline in the minimally invasive group at these intervals versus 77% and 74% in the conventional control group (p = not significant). Myocardial temperatures were similar throughout bypass in the two groups, and ultrastructural examination of prebypass and postbypass biopsy specimens showed no differences between groups. These results demonstrate that minimally invasive cardiopulmonary bypass with cardioplegic arrest is as feasible, safe, and effective as conventional open chest cardiopulmonary bypass. Thus current technology may allow wider clinical application of closed chest cardiac surgery.

Isolated right ventricular outflow tract mass presenting as hemoptysis.

Infective endocarditis presenting as an isolated right ventricular outflow tract mass is rare. We report a 34-year-old man with no history of congenital heart defect or intravenous drug abuse who presented with hemoptysis and fevers. Diagnostic workup revealed isolated right ventricular outflow tract vegetation. Despite aggressive antibiotic treatment for endocarditis, he developed septic emboli and acute respiratory distress. He was taken to the operating room for successful resection of the ventricular mass.

Regional topical hypothermia of the beating heart: preservation of function and tissue.

BACKGROUND: Protection of the myocardium during beating heart operations is paramount. The goal of this study is to determine if regional topical hypothermia (RTH) preserves myocardial viability and function during periods of temporary coronary artery occlusion. METHODS: Sixteen pigs were divided into two groups (RTH and control). Each group received 40 minutes of midleft anterior descending coronary occlusion followed by 3 hours of reperfusion. The RTH group (n = 10) received RTH and the control group (n = 6) received no cooling. Myocardial and core temperatures were measured with thermistors. Sonomicrometers and micromonameters were used to determine load independent indices of myocardial function. These indices were measured at base line, during coronary occlusion, and at 3 hours of reperfusion. The myocardium at risk and the infarct area were determined with monastral blue dye and triphenyl tetrazolium chloride staining. RESULTS: The mean myocardial temperature in the risk zone during coronary occlusion was significantly less in the RTH group (29.4 degrees C +/- 5.6 degrees C versus 35.7 degrees C +/- 1.1 degrees C, p < 0.05). After 40 minutes of coronary occlusion, both the RTH group and control had a significant reduction in regional elastance (9.38 +/- 3.54 and 11.05 +/- 1.67 mm Hg/mm) compared with base line measurements (14.70 +/- 2.42 and 16.80 +/- 4.79 mm Hg/mm), p < 0.05. However, after 3 hours of reperfusion, the elastance returned to base line levels in the RTH group (15.83 +/- 3.06 mm Hg/mm) but remained significantly depressed in the control group (9.97 +/- 3.63 mm Hg/mm, p < 0.04). Myocardial necrosis as a percentage of the risk zone was significantly less in the hypothermia group (25% +/- 2% versus 62% +/- 5%, p < 0.001). CONCLUSIONS: Regional topical hypothermia during isolated temporary coronary occlusion provides regional myocardial protection expressed as a return of function and decreased necrosis. Regional topical hypothermia may be clinically applicable to myocardial preservation during beating heart operations.

Wound healing after harvesting of the internal thoracic and the superior and inferior epigastric arteries.

Wound healing of sternal incisions and midline or paramedian abdominal incisions was studied at 2 weeks postoperatively in three groups of dogs. Group 1, 10 dogs, had harvesting of bilateral internal thoracic arteries, superior epigastric arteries, and inferior epigastric arteries. Group 2, 5 dogs, had removal of the same arteries, but the superior and inferior epigastric arteries were harvested through paramedian rather than midline incisions. Group 3, 5 dogs, served as control and had median sternotomies and midline abdominal incisions only. All wounds healed without complication. Wound breaking strength of the skin of the chest incisions was significantly greater (p < 0.05) in the control group (group 3) (52.6 lb) compared with groups 1 (38.0 lb) and 2 (34.8 lb). Wound breaking strength of the skin of the abdominal incisions was significantly greater (p < 0.05) in group 2 (50.4 lb) when paramedian incisions were made compared with group 1 (35.1 lb). Hydroxyproline content was similar for all groups and all incisions. We conclude that abdominal wound breaking strength is significantly greater when paramedian incisions are performed to harvest the inferior epigastric arteries. Harvesting bilateral internal thoracic, superior epigastric, and inferior epigastric arteries may lower sternal wound breaking strength.

Combined maze procedure and septal myectomy in a septuagenarian.

A 75-year-old woman with refractory paroxysmal atrial fibrillation and hypertrophic obstructive cardiomyopathy underwent a successful combined maze procedure and septal myectomy. Postoperative episodes of atrial fibrillation and flutter occurred only during periods of bradyarrhythmia and did not recur with atrial inhibited pacing.

Early results of posterior leaflet folding plasty for mitral valve reconstruction.

BACKGROUND: Standard reconstruction for posterior mitral leaflet (PML) disease is quadrangular resection and annular plication; when the PML is excessively high, a sliding plasty is used. We have developed an alternative technique, a posterior leaflet folding plasty. It is performed by folding down the cut vertical edges of the PML. The central height of the PML is reduced, leaflet coaptation is moved posteriorly, and annular plication is unnecessary. METHODS: From March 1995 to August 1996, 26 (17.9%) of 145 patients undergoing mitral reconstruction had a posterior leaflet folding plasty. Concomitant procedures included anterior leaflet resection or resuspension and myotomy and myectomy. In 3 patients, the PML resection extended to a commissure. RESULTS: There was one death and no reoperations. The mean New York Heart Association class was improved from 2.4 preoperatively to 1.4. There was no major postoperative mitral insufficiency in the 26 patients. Systolic anterior motion was transiently seen in 1 patient in whom left ventricular outflow tract obstruction was present preoperatively. CONCLUSIONS: The data demonstrate the safety and short-term efficacy of posterior leaflet folding plasty. This technique may help avoid systolic anterior motion after reconstruction of the PML.

Effect of cannula length on aortic arch flow: protection of the atheromatous aortic arch.

Atheromatous disease in the transverse aortic arch is associated with an increased incidence of perioperative stroke. In addition, tissue erosion in the aortic arch is caused by the high-velocity jet emerging from an aortic cannula during cardiopulmonary bypass (CPB), termed the "sandblast effect". To quantify this phenomenon, flow in the aortic arch was measured intraoperatively by epiaortic ultrasonography in 18 patients undergoing CPB. All were cannulated in the ascending aorta, 10 with a short (1.5 cm) cannula and 8 with a long (7.0 cm) cannula. The peak forward aortic flow velocities (mean +/- standard deviation) measured on the caudal luminal surface of the aortic arch were 0.80 +/- 0.23 m/s off CPB and 2.42 +/- 0.69 m/s on CPB (p < 0.001) for the short cannula and 0.53 +/- 0.20 m/s off CPB and 0.18 m/s on CPB for the long cannula. Thus, during CPB the peak forward aortic flow velocity with the short cannula was significantly greater (p < 0.001) than before CPB, whereas the long cannula produced a lower peak forward aortic flow velocity during CPB. Furthermore, Doppler examination revealed severe turbulence in the aortic arch in all patients with a short cannula. No arch turbulence, however, was seen in 7 patients with a long cannula, and only mild turbulence appeared in the remaining patient with a long cannula. These results show that use of a long aortic cannula results in a significant decrease in peak forward aortic flow velocity and turbulence in the aortic arch during CPB, which may reduce the risk of erosion or disruption of existing atheroma and ensuing embolic complications.

Heparin bonding of bypass circuits reduces cytokine release during cardiopulmonary bypass.

BACKGROUND: Heparin bonding of the cardiopulmonary bypass (CPB) pump circuit decreases complement activation and fibrinolysis. It is not known whether inflammatory cytokines produced during CPB can also be modulated by the more biocompatible heparin-coated circuit. METHODS: This initial study evaluated the impact of heparin-bonded CPB circuits on production of the cytokines interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-a), IL-6, and IL-8 in adults undergoing complex cardiac operations with prolonged CPB. Twenty patients had blood samples drawn immediately before and at hourly intervals after the start of CPB using either a conventional oxygenator and circuit (n = 14) or a covalently bonded heparin oxygenator and circuit (n = 6). Levels of IL-1, TNF-a, IL-6, and IL-8 were measured in all serum samples using a "sandwich" enzyme-linked immunosorbent assay. RESULTS: The levels of IL-6 and IL-8 increased in a time-dependent fashion in both groups, but the response was significantly less over time in the heparin-bonded group (p < 0.05) for both IL-6 and IL-8. Levels of IL-1 and TNF-a were not significantly elevated with lengthening bypass interval in either group. CONCLUSIONS: These data indicate that the use of heparin-coated bypass pump circuits results in lower serum levels of the inflammatory cytokines IL-6 and IL-8 than standard circuits. Biocompatible materials that decrease the inflammatory response to CPB may ultimately reduce the morbidity associated with cardiac operations.

Selective approach to descending thoracic aortic aneurysm repair: a ten-year experience.

BACKGROUND: A variety of surgical techniques has been developed to attempt to minimize the risk of paraplegia after descending thoracic aortic aneurysm repair. This study reviews our institutional experience with several basic techniques over a period of 10 years. METHODS: Seventy-eight consecutive patients underwent repair of descending thoracic aortic aneurysm between 1983 and 1993. Two basic repair strategies were used: (1) distal perfusion with somatosensory evoked potential monitoring (n = 54) and (2) cross-clamping (n = 24), alone (n = 6) or with controlled distal exsanguination (n = 18). RESULTS: The operative mortality rate was 6.5% for elective repair (n = 62), 25.0% for emergent repair (n = 16), and 10.3% overall. Univariate predictors of increased operative risk were emergent operation, rupture, and shock. Neither death nor paraplegia was related to the operative technique used. The incidence of paraplegia was 3.7% in perfused patients and 4.2% in cross-clamping patients (p > 0.05). Paraplegia did not occur after any elective operation (zero of 62) but occurred in 18.6% of emergent cases (p < 0.01). In perfused patients, paraplegia did not occur when the distal pressure was maintained above 55 mm Hg and somatosensory evoked potentials remained intact. When somatosensory evoked potentials were lost (n = 7) in perfused patients, the operative technique was altered successfully in 5 patients, whereas in 2 patients (28.6%), paraplegia developed. CONCLUSIONS: The risks associated with elective descending thoracic aortic aneurysm repair were extremely low using an operative strategy that was flexible but skewed toward perfusion with somatosensory evoked potential monitoring. In perfused patients, paraplegia did not occur when distal pressure was greater than 55 mm Hg and somatosensory evoked potentials remained intact. However, the risks of death and paraplegia were primarily related to emergent presentation, not to technique, and the technique of cross clamping with controlled distal exsanguination was found to be valuable in unstable or in anatomically complicated subsets of patients.

Imaging of surgical diseases of the newborn chest. Intrapleural mass lesions.

Prenatal detection of intrapleural mass lesions is commonplace. Diagnostic treatment plans often are formulated before birth. The radiologist's involvement in dealing with congenital lobar emphysema, congenital cystic adenomatoid malformation, extralobar pulmonary sequestration, and congenital diaphragmatic hernia has changed. The need for immediate postnatal diagnosis has been de-emphasized, but the demand for precision and efficiency in preoperative cross-sectional imaging, monitoring progress and complications of treatment, and assistance with nutritional support has increased.

Maturational descent of the epiglottis.

BACKGROUND: Otolaryngologists and anesthesiologists have described a maturational descent of the epiglottis that occurs in infancy and childhood. OBJECTIVE: To investigate the changing level of the epiglottis to confirm and characterize this phenomenon more completely. DESIGN: A survey of 500 images with 338 images selected for the study. SETTINGS: A tertiary care facility. PATIENTS: Asymptomatic children aged 1 day to 18 years. MAIN OUTCOME MEASURE: The position of the tip of the epiglottis was correlated with the cervical vertebral level. RESULTS: Data indicate that maturational descent of the epiglottis starts in infancy and continues into adolescence. These results are statistically significant (P < .01). CONCLUSION: Maturational descent of the epiglottis occurs in a predictable pattern. Understanding this phenomenon may facilitate laryngoscopic, as well as clinical and radiologic, evaluation of the airway in children.

Histological evaluation of the inferior epigastric artery in patients with known atherosclerosis.

Comparative histological studies have been performed on the various arterial conduits available for myocardial revascularization including the inferior epigastric artery which has recently become the focus of intense investigation. In this study, 10 patients with known risk factors for atherosclerotic disease had their inferior epigastric artery harvested and the entire specimen examined for the microscopical presence of atherosclerosis or its precursors. Histopathological findings that have been shown to be theoretically protective against the progression of atherosclerosis were observed. These include the paucity of fenestrae in the internal elastic lamina, no medical calcification, the absence of foam cells and the absence of intimal smooth muscle cells. No specimen had atherosclerotic disease and only 3 specimens showed changes consistent with minimal intimal hyperplasia. Morphometric analysis of the 3 diseased specimens revealed only minimal luminal narrowing. These findings suggest that the inferior epigastric artery may not be prone to atherosclerosis. Thus, the inferior epigastric artery appears to be a safe myocardial conduit and long-term patency can be anticipated.

Metachronous primary carcinomas of the lung in an HIV-infected patient.

Studies have suggested that human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients have an increased risk of developing primary lung cancer, with a poor prognosis. We report a 59-year-old HIV-seropositive man who developed two metachronous primary bronchogenic carcinomas with different histologic features. The initial tumor was cured after early diagnosis and resection, with subsequent development of a contralateral tumor 6 years later. The case emphasizes that early diagnosis and treatment of lung cancer in HIV/AIDS patients should be sought as they may improve their short-term prognosis. However, because of their immunocompromised state, extended survival is still limited by a higher likelihood of developing subsequent malignancies.

Radiographic findings and patterns in multidrug-resistant tuberculosis.

Multidrug-resistant tuberculosis (MDR TB) is prevalent in urban areas with large HIV-positive populations. We retrospectively evaluated the chest radiographs of MDR TB patients at presentation and compared them to patients with drug-sensitive tuberculosis (DS TB). Although the overall radiographic findings and patterns of MDR TB and DS TB were similar, there were significant differences among the MDR TB patients depending on how MDR TB was acquired. Patients who developed MDR TB during an outbreak showed noncavitary consolidations, pleural effusions, and a primary radiographic pattern (70%). On the other hand, patients who acquired MDR TB due to noncompliance with antituberculous therapy often had cavitary consolidations (50%) and generally demonstrated a postprimary radiographic pattern. Cavitation occurred equally in patients with MDR TB who are HIV positive regardless of CD4 cell count. Chest radiographic findings and patterns in MDR TB are most accurately interpreted in conjunction with clinical history, specifically prior TB treatment. Nevertheless, approximately one-third of patients did not show the "expected" radiographic pattern.

Hemodynamic and electrocardiographic effects of graded doses of amiodarone in healthy dogs anesthetized with morphine/alpha chloralose.

This research was designed to study acute hemodynamic and electrocardiographic effects of amiodarone and to determine an IV dose of amiodarone that minimally affects left ventricular function and does not increase the tendency for ventricular arrhythmia.