A novel approach to coronary revascularization in patients with severely diseased aorta.

Atheromatous disease of the aorta significantly increases morbidity and mortality during coronary revascularization. The surgical approach must be modified for patients in whom this condition is identified. In this report, we describe a technique that uses bilateral internal thoracic arteries as composite grafts with reverse saphenous veins. The operation is performed without cardiopulmonary bypass. We report the cases of 2 patients who underwent this procedure. Neither patient experienced signs or symptoms of atheromatous embolization, and there was no perioperative morbidity or mortality. Off-pump myocardial revascularization using bilateral internal thoracic arteries is an attractive surgical approach for patients who have atheromatous aortas or other conditions in which it is advantageous to avoid aortic manipulation, cannulation, cross-clamping, and cardiopulmonary bypass.

Occlusion of left coronary artery ostium by an aortic valve cusp.

Congenital anomalies of the aortic valve can be associated with other cardiac anomalies. In this report, we present a patient with an aortic valve anomaly associated with occlusion of left coronary ostia. In addition, we reviewed the literature and found 10 similar cases. Although compatible with life, this anomaly can lead to significant symptoms. Preoperative diagnosis as well as proper therapeutic planning should be tailored to correct valvular competence and restore coronary blood flow.

Is there a role for routine mediastinoscopy in patients with peripheral T1 lung cancers?

BACKGROUND: The role of surgical staging of patients with non-small cell lung cancer (NSCLC) continues to evolve. This report describes our findings utilizing routine cervical mediastinoscopy in the evaluation of peripheral T1 (<3 cm) lung tumors. METHODS: Retrospectively 30 patients with peripheral T1 lesions and CT scans negative for pathologic adenopathy were identified over a 3-year period. Cervical mediastinoscopy was performed prior to VATS/thoracotomy during the same operative session. RESULTS: Mediastinoscopy was performed in 29 of 30 patients. For patients with malignancy (27 of 30), 3 of 27 (11%) had mediastinoscopy positive for malignancy and no further resection performed. Overall the subgroup of patients with bronchogenic carcinomas had positive mediastinal involvement identified in 5 of 24 (21%) after mediastinoscopy or complete resection. CONCLUSION: A significant number of patients with small peripheral lung cancers harbor radiographically occult lymph node involvement. Mediastinoscopy facilitates identification of patients with regionally advanced disease prior to resection, allowing neoadjuvant therapy and avoiding unnecessary resections.

Giant aneurysm of saphenous vein graft to coronary artery compressing the right atrium.

Aneurysm of reverse aortocoronary saphenous vein graft is a known complication of coronary artery bypass grafting. In this report we present a case of a 60-year-old man who presented 12 years after coronary artery bypass grafting with a giant graft aneurysm of the reverse aortocoronary saphenous vein graft to the right coronary artery, compressing the right atrium. Spiral computed tomography was used to identify the aneurysm measuring 7 x 6 x 7 cm. We also reviewed the English-language literature and found reports of 50 patients with similar aneurysms of which 30 (61%) were identified as true aneurysms and 17 (33%) were identified as pseudoaneurysms. Three patients could not be identified into either group. We reviewed the presenting symptoms, diagnostic tools, and treatment options for this rare entity. An understanding of the pathophysiology of reverse aortocoronary saphenous vein graft aneurysm is important to prevent the possibility of aneurysm rupture, embolization, myocardial infarction, or death.

Changes in pulmonary mechanics after lung volume reduction surgery.

Lung volume reduction surgery (LVRS) is a promising new treatment for emphysema and leads to increased flow rates. We investigated the mechanisms by which flow rates could increase and the correlates of lessened dyspnea in patients undergoing LVRS before and 3 months after LVRS in patients with severe emphysema. The following were done: routine pulmonary function testing, measurements of elastic recoil (Pel), tidal breathing patterns, inspiratory work of breathing (Winsp), construction of static recoil-maximum flow curves, and measurement of baseline and transitional dyspnea index (TDI). There were increases in forced vital capacity (FVC: 2.24 +/- 0.71 to 2.92 +/- 0.63 liters; p < 0.05), forced expired volume in 1 (FEV1: 0.64 +/- .16 to 1.03 +/- 0.28 liters; p < 0.01), and decreases in all divisions of lung volume, e.g. total lung capacity (TLC: 6.86 +/- 1.41 to 5.96 +/- 1.49 liters; p < 0.01). Maximum Pel increased (11.7 +/- 3.7 to 19.8 +/- 7.8 cmH2O; p < 0.02) as did the coefficient of retraction (CR = Pel/TLC: 1.8 +/- 0.7 to 3.6 +/- 3.6 +/- 2.2 cmH2O/liter). However, the individual responses in other parameters were markedly different among patients. There was no consistent trend in changes in the slope or position of the static recoil-maximum flow curve or Winsp. The only positive correlate of improved dyspnea (TDI = 3.22 +/- 2.22; p < 0.01) was improvement in CR, FEV1 being a weak negative correlate and change in lung volume not being a correlate at all. We conclude that there is a heterogeneous response of the airways to LVRS. Increased elastic recoil was the primary determinant of improved flow rates after LVRS and is the only positive correlate for improvement in dyspnea.

Routine myocardial revascularization with the radial artery: a multicenter experience.

BACKGROUND: Current literature documents use of the radial artery (RA) for myocardial revascularization only as an alternative conduit in cases where the saphenous veins have been previously harvested or are unsuitable for use. Large-scale routine clinical use of the RA as the conduit of choice has not been reported. METHODS: This prospective study evaluated the harvest of the RA from 933 patients and the subsequent use of the conduit as a preferred coronary artery bypass graft second only to the left internal thoracic artery in 930 of these patients. RESULTS: Unilateral RA harvest was performed in 786 patients and 147 patients had bilateral RA harvest. A total of 1080 RAs were harvested; 214 (19.8%) originated from the dominant forearm. There was a mean of 3.30+/-0.93 grafts per patient of which 2.43+/-0.83 were arterial grafts. The mean number of RA grafts was 1.43+/-0.53. Operative mortality was 2.3% with none due to the RA graft(s). There was no ischemia nor motor dysfunction in the operated hands. Thirty-two (3.4%) patients experienced transient thenar dysesthesia that resolved in 1 day to 6 weeks. CONCLUSIONS: Our results demonstrate that routine total or near total arterial myocardial revascularization may be achieved safely and effectively with the use of one or both RAs in conjunction with the internal thoracic artery.

Aortic valve replacement with a pulmonary autograft: case studies of the Ross procedure.

The Ross procedure is an old surgical technique that is gaining popularity some 30 years after its introduction. The patient's own pulmonary valve is essentially used as a "spare part" to replace the diseased aortic valve. The Ross procedure has become an accepted and attractive option for patients with a life expectancy of more than 20 years and for patients in whom long-term treatment with anticoagulants is undesirable or problematic. Careful preoperative evaluation and postoperative management, as well as proficient surgical techniques, are all necessary to achieve good outcomes.

Speech and swallowing rehabilitation following devastating caustic ingestion: techniques and indicators for success.

Caustic material ingestion, either accidental or intentional, may result in tissue and organ destruction leading to a wide range of complications, including loss of speech and the ability to eat. The esophagus can be reconstructed successfully, but reopening the larynx and upper airway poses a significant therapeutic dilemma. External reconstruction may put the neoesophagus at risk. Loss of the normal swallowing mechanism and the protective supraglottic structures often results in fatal aspiration. The authors present three cases of successful endoscopic laser recannulation of the larynx with esophageal replacement. The discussion includes surgical technique and the tools used to determine the success of the reconstruction, including computed tomographic scanning, modified barium swallow, placement of an upper esophageal anastomosis, psychologic support, and speech and swallowing therapy.

Effects of continuous positive airway pressure on cardiac output in normal and hypervolemic unanesthetized pigs.

Continuous positive airway pressure (CPAP) has been used to increase cardiac index (CI) in patients with congestive cardiomyopathy in the presence of elevated pulmonary wedge pressure. We hypothesized that with normovolemia, CPAP would decrease CI because of decreased left ventricular (LV) preload, whereas in hypervolemia CPAP would increase CI because of a decrease in afterload. We tested this hypothesis on nine sedated, unanesthetized pigs instrumented 5 to 10 d before study. We measured CI, heart rate, stroke volume, LV end-diastolic and end-systolic pressures, and LV dimensions at CPAP levels 0, 5, 10, 15, and 20 cm H2O before and after volume expansion with hetastarch (35 ml/kg). From LV dimensions, LV end-diastolic (LVEDV) and LV end-systolic volumes (LVESV) and LV ejection fraction (LVEF) were calculated. With normovolemia, CI and LVEDV decreased with increased CPAP. Volume infusion produced mild cardiac dysfunction as evidenced by increased LV volumes, decreased LVEF, and decreased contractility. With hypervolemia, CPAP produced an increase in CI, decrease in LVEDV and LVESV, and an increase in LVEF. At higher values of CPAP, we observed decreased CI and LVEDV as with normovolemia. We conclude that with normovolemia, CPAP's effects are mainly related to changes in preload. Hypervolemia produced mild cardiac dysfunction. The improvement in CI with CPAP appears predominantly to be secondary to decrease in LV afterload, but a mild preload effect, which parallels the effect seen with normovolemia, was superimposed on afterload changes at higher CPAP values.

Respiratory phasic effects of inspiratory loading on left ventricular hemodynamics in vagotomized dogs.

Exaggerated inspiratory swings in intrathoracic pressure have been postulated to increase left ventricular (LV) afterload. These predictions are based on measurements of LV afterload by use of esophageal or lateral pleural pressure. Using direct measurements of pericardial pressure, we reexamined respiratory changes in LV afterload. In 11 anesthetized vagotomized dogs, we measured arterial pressure, LV end-systolic (ES) and end-diastolic transmural (TM) pressures, stroke volume (SV), diastolic left anterior descending blood flow (CBF-D), and coronary resistance. Dogs were studied before and while breathing against an inspiratory threshold load of -20 to -25 cmH2O compared with end expiration. Relative to end expiration, SV and LVES TM pressures decreased during inspiration and increased during early expiration, effects exaggerated during inspiratory loading. In all cases, LV afterload (LVES TM pressure) changed in parallel with SV. LV end-diastolic TM pressure did not change. CBF-D paralleled arterial pressure, and there were no changes in coronary resistance. In two dogs, regional LVES segment length paralleled calculated changes in LVES TM pressure. We conclude that 1) LV afterload decreases during early inspiration and increases during early expiration, changes secondary to those in SV; 2) changes in CBF-D are secondary to changes in perfusion pressure during the respiratory cycle; and 3) the use of esophageal or lateral pleural pressure to estimate LV surface pressure overestimates changes in LV TM pressures during respiration.

Cardiovascular effects of periodic occlusions of the upper airways in dogs.

Hypoxemia and decreased intrathoracic pressure have been postulated as contributing causes of cardiovascular morbidity in obstructive sleep apnea syndrome (OSAS). Because of the difficulty of manipulating experimental conditions in humans, we developed an anesthetized closed-chest dog model, simulating the periodic airway occlusions of OSAS by periodic occlusions of the endotracheal tube (PUO). Using a periodicity of 60 s occluded, followed by 60 s ventilation for five to seven cycles, we measured heart rate (HR), cardiac output (CO), arterial pressure (Pa); left ventricular (LV) end-diastolic and end-systolic transmural pressure; dp/dt of LV pressure; left anterior descending (LAD) coronary blood flow (CBF), and regional myocardial contractility and intramyocardial pH. Four experimental conditions were studied: room air (RA) breathing (PO2 = 40); 100% O2 breathing (O2), and RA and O2 breathing with critical LAD stenosis (CS). Under all conditions PUO produced decreases in CO (10 to 30%) and proportional decreases in Pa. HR decreased, and in all but RA conditions stroke volume was unchanged. During the obstructed phase, indices of LV preload decreased. Indices of LV afterload also decreased except for LAD-perfused myocardium under RACS conditions. This latter was shown to be associated with regional ischemia (decreased regional pH and shortening). Regional ischemia was also demonstrated in two of nine dogs even under O2CS conditions. Among our major conclusions: (1) decreased Pa during PUO is due to decreased CO; (2) LV afterload does not increase during PUO; (3) with limited coronary flow reserve (CS), PUO can lead to myocardial ischemia. This is mostly but not solely due to hypoxia.

Effects of inspiratory loading on left ventricular myocardial blood flow and metabolism.

With airways obstruction, mean pleural pressure decreases. It has been postulated that associated increases in left ventricular afterload increase myocardial O2 demand (MvO2) and coronary blood flow (CBF). We tested this hypothesis in 12 anesthetized mixed-breed dogs. Through a median sternotomy, dogs were instrumented for the measurement of mean arterial pressure, cardiac output, and left anterior descending CBF. A catheter placed in the coronary sinus allowed sampling of left ventricular venous blood. MvO2 was calculated as CBF x (arteriovenous content difference), and coronary resistance was calculated as (mean arterial pressure)/CBF. After closure of the thoracotomy, animals were studied before and during inspiratory threshold loading (IL) of -20 to -25 cmH2O while breathing 100% O2 before and after bilateral cervical vagotomy. During IL, heart rate fell [approximately 20 beats/min (NS prevagotomy, P less than 0.05 postvagotomy)], arterial PCO2 increased [45 to 66 Torr prevagotomy, 45 to 50 Torr postvagotomy (P less than 0.01)], and arterial O2 content was unchanged. CBF increased with IL:41% prevagotomy (P less than 0.01), 18% postvagotomy (P less than 0.02). However, with IL, MvO2 did not increase significantly either pre- or postvagotomy. Coronary resistance decreased with IL [30% prevagotomy, 24% postvagotomy (P less than 0.01)]. In eight dogs, PCO2 was increased by increasing dead space while the animals were mechanically ventilated and paralyzed. Although there was little change in CBF, heart rate fell by an amount equal to that with IL. We conclude that 1) IL causes coronary vasodilation not related to changes in MvO2, PCO2, or vagal tone; 2) MvO2 does not increase with IL; and 3) decreased heart rate with IL is related to hypercapnia and/or acidosis.

In vivo inactivation of antithrombin III is promoted by heparin during cardiopulmonary bypass.

To study the in vivo effect of heparin on antithrombin III (AT3) when elastase is elevated, the blood of 20 patients undergoing cardiopulmonary bypass (CPB) was assayed for elastase and AT3. The model was chosen because CPB is known to increase plasma elastase and the patients were heparinized. The blood of 20 patients undergoing cardiac surgery was assayed for elastase and AT3 one day preoperatively, every half hour during CPB, and one day postoperatively. Elastase increased significantly and AT3 decreased significantly during CPB. There was a direct correlation between the rise in elastase and decrease in AT3. AT3 decreased even further when elastase was elevated and patients were heparinized (AT3/elastase = 0.04 + 0.07), compared with the drop with elevated elastase alone (AT3/elastase = 0.11 + 0.14) (P less than .0015). These data indicate that (1) CPB is associated with an increase in plasma elastase, (2) elevated plasma elastase is associated with a reduction in AT3, and (3) heparin promotes the inactivation of AT3 when serum elastase is increased. These data confirm the in vitro observation that heparin accelerates the inactivation of AT3 in the presence of elastase.