Watts R. Webb

Prophylactic digitalization for coronary artery bypass surgery.

One hundred and twenty patients undergoing aortocoronary bypass procedures were randomly placed into control and digitalized groups. All were initially in normal sinus rhythm and without evidence of congestive heart failure. Supraventricular arrhythmias occurred in 17 of 66 controls and in only three of 54 digitalized patients (P < 0.01). There was no evidence of digitalis toxicity. Based on this evidence we recommend prophylactic digitalization for patients having aortocoronary bypass operations.

Comparison of Patients with Coronary Artery or Valve Disease: Intraoperative Differences in Blood Volume and Observations of Vasomotor Response

A review of 296 patients undergoing cardiac operations has shown that those with coronary artery disease have a blood volume deficit. The 148 patients with valve disease had a normal blood volume of 78 ml/kg (normal range, 68--88 ml/kg), while the 148 coronary artery disease had a blood volume of 69 ml/kg (p less than 0.001). Infusion of plasma prior to cardiopulmonary bypass as well as the total transfusion required afterward to maintain blood pressure indicated an important clinical difference in these two groups. Another finding was that the requirement for a drug to control blood pressure prior to use of cardiopulmonary bypass was greater in the coronary patients (p less than 0.01). Comparison of the requirement for a hypotensive agent before and after bypass showed a greater predictability in the valve group. This experience leads us to conclude that patients with coronary artery disease and angina not only have a low blood volume, but they also have a marked vasoactive lability which shows up in their hemodynamic response to the conduct of an operation and to anesthesia.

Retrograde Pressures and Flows in Coronary Arterial Disease

Abstract Antegrade and retrograde pressures and flows have been measured in the coronary arteries distal to an obstructive lesion and the retrograde flow and pressure correlated with the arteriographically determined degree of stenosis and extent of collateral circulation. Antegrade pressure and flow were roughly proportional to the estimated degree of proximal obstruction, with little change being noted below 70% obstruction. Below 90% obstruction, minimal collateral flow was demonstrable either by arteriogram or by retrograde flow measurement. Retrograde pressures proved to be surprisingly low, usually being about one-third of the systemic pressure and almost never over 30 mm. Hg. Retrograde pressures were relatively independent of the degree of proximal stenosis or of arteriographically demonstrable collateral circulation. Retrograde flows likewise proved to be surprisingly small, even though the method of measurement allowed for absolutely maximal backflow. Retrograde flow, however, did correlate well with the degree of collateral circulation demonstrated in the arteriograms. Patients with the preinfarction syndrome had the lowest antegrade flows and retrograde flows, which were usually too small to be measured.

Experimental Pulmonary Edema: The Effect of Positive End-Expiratory Pressure on Lung Water

The effect of 10 cm of positive end-expiratory pressure (PEEP) on lung water was studied during pulmonary edema induced in dogs by inflating a Foley balloon placed in the left atrium. Colloid oncotic pressure (COP) was measured directly. Intrapleural pressure (IPP) was measured after surgical closure of the chest. Transmural left atrial (LA) pressure (LA minus IPP) minus COP was considered to be the net force driving water out of the capillaries. LA pressure was elevated so that transmural LA pressure minus COP averaged +7.5 mm Hg. Water accumulation was expressed as the ratio of wet to dry weight. The control ratio of wet to dry lung weight was 4.30 +/- 0.10 (+/- SE). After 2 hours of standardized pulmonary edema and ventilation without PEEP, wet-to-dry lung weight was 5.63 +/- 0.24. In animals ventilated with 10 cm of PEEP through 2 hours of pulmonary edema the ratio was 5.36 +/- 0.14. Animals ventilated with 10 cm of PEEP showed a significant increase in functional residual capacity and decreased intrapulmonary shunt. Ten centimeters of PEEP, however, had no statistically significant effect on water accumulation during experimental pulmonary edema.

Management of Acute Aortic Dissection

The therapy for acute dissecting aneurysm of the aorta remains a difficult problem for thoracic surgeons. Because of an excessive operative mortality in patients with acute dissection who were operated on within 24 hours of hospital admission, we have utilized intensive medical management to delay surgical intervention. Even patients with acute aortic insufficiency can be supported medically, allowing their operations to be delayed at least 3 weeks or longer. Since this policy has been implemented, there has been no operative mortality in our last 13 patients with acute dissection. Medical therapy as the definitive treatment is now reserved solely for Type III dissections or for patients who cannot be operated on for other reasons. This report outlines our rationale for therapy and our current method of managing acute dissection.

Gas Endarterectomy of Right Coronary Artery The Importance of Proximal Bypass Graft

Results of gas endarterectomy of the right coronary artery were evaluated in 29 consecutive patients. There were one surgical and two early postsurgical deaths. All three had postmortem examination, and in two there was occlusion of the gas endarterectomy. Five patients did not have repeat catheterization. Twenty-one patients were completely re-evaluated and had repeat cardiac catheterization one to sixteen months after surgery (mean eight months). Ten patients (Group A) had gas endarterectomy without a saphenous vein graft to the right coronary artery. Only one patient had significant vessel patency. Eleven patients (Group B) had the combined procedure of a saphenous vein graft anastomosed to the segment of artery that had the endarterectomy. There was excellent graft patency in seven patients (64%) and good distal flow into the segment that had endarterectomy in six of the seven patients. In conclusion, gas endarterectomy is not of value unless it can be combined with a saphenous vein graft to provide good flow to the distal vessel that had endarterectomy. Results with the combined procedure suggest that even with a severely diseased artery, gas endarterectomy can often provide continuing distal runoff for the graft.

Cinemicroscopy of Hyperacute Pulmonary Rejection

Rejection processes were studied in xenografts and allotransplants of cat or dog lungs to dogs. Cinemicroscopy of the microcirculation in untreated animals showed almost immediate sludging, cellular aggregation, reduced vascular caliber, diminished blood flow, and rapid development of perivascular edema. The principal mechanisms of the extremely rapid xenograft rejection include capillary and arteriolar obstruction due to cellular aggregation. Pretreatment with heparin was virtually valueless, while methylprednisolone offered temporary protection.

Pulmonary Complications in Primary Acquired Hypogammaglobulinemia: Surgical Considerations

With the discovery and routine use of antibiotics, a virtually new disease--primary acquired hypogammaglobulinemia--was recognized. More precise clinical, genetic, and laboratory endeavor has proved, in fact, that it is really one of a whole host of individual disease entities, all with the common feature of inadequate production and marshalling of gamma globulin to combat infection. Although the condition has been recognized in childrens medicine for two decades, the survival of these early victims into adolescence and adulthood is now bringing them to the attention of surgeons as candidates for drainage or resection of suppurative disease of the lung, air tubes, and pleura. In fact a triad has emerged, with some of these patients having infectious disease in the lungs and sinuses associated with enlargement of the spleen when first seen. Often it is the radiologist who first suspects the diagnosis when he recognizes one or more features of this diagnostic triad. Three personal cases are presented together with a technique of management that appears successful. As with the recognition of any new disease, occult and subclinical presentations become more common as suspicion progresses, and ease of confirmation is afforded.

Ventricular Septal Defect due to Septal Infarction after Repair of Tetralogy of Fallot

A case is reported of ventricular septal defect resulting from septal infarction following repair of a tetralogy of Fallot. The infarct probably resulted from division of a septal coronary artery during resection of the hypertrophied infundibulum. The superficial position of the septal artery on the right side of the septum in tetralogy makes it surprising that this complication has not been previously reported.

Red Cell Interactions with the Microcirculation

We have measured RBC velocity profiles for mammalian arterioles and venules from high-speed cinematographic motion pictures. Measurements were made at 320× and 400× optical magnification over an averaging time period of 10 ms. In vivo profiles are uniformly nonsymmetrical, the RBCs exhibit rotation, and they frequently deviate sidewise from the overall axial direction of motion. In general, this is more pronounced on the venous side. Since all of the profiles are time variant and the average values are synchronous with the midstream velocity, individual RBC velocities will vary about the average. Profiles become more blunted in vessels with smaller diameters. In vessels below 16 μm diameter, the velocity gradients between adjacent RBCs are quite small; for large vessels, recognizable profiles develop and become fully developed in blood vessels above 30 μm in diameter. This blunting is further affected by the midstream velocity and the local hematocrit; when the velocity is reduced below 1.2 mmls and/or an increased hematocrit is present, the profile becomes more blunted.