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N L Mills

Publications and source records attributed to N L Mills.

At least 37 records · Page 2Linked to original sources
PubMed1991

Technical considerations for myocardial protection during the course of coronary artery bypass reoperation: the impact of functioning saphenous vein and internal mammary artery grafts.

New technical challenges involving the delivery of cardioplegia during the course of coronary artery bypass operation continue to be presented to the surgeon. Functioning saphenous grafts at reoperation that are at risk for distal embolization, are managed by altering the standard cardioplegia delivery techniques. Management of patent internal mammary artery (IMA) grafts depends upon the status of the native circulation and coronary collateral. The reoperation may be performed with a fibrillating heart, standard cardioplegia with a clamped mammary graft, or cardioplegia delivered during simultaneous circulatory arrest. Myocardial temperature measurements, during the course of more complex operations, are useful in choosing the appropriate technique for myocardial protection.

Collateral Circulation↗
PubMed1991

Atherosclerosis of the ascending aorta and coronary artery bypass. Pathology, clinical correlates, and operative management.

Analysis of 1735 patients who underwent coronary artery bypass grafting from January 1981 through December 1988 revealed 152 (8.8%) patients with mild (4.5%), moderate (2.2%), or severe (2.0%) atherosclerosis of the ascending aorta. Three distinct pathologic patterns were found. The prevalence of stroke in patients with the severe type of aortic disease prompted development of a new operative technique that has been used in 16 patients. It involves a "no-touch" technique of the ascending aorta whereupon the proximal saphenous vein anastomoses are performed end to side to internal mammary artery grafts. Ages ranged from 49 to 80 years (mean 68.9). The 16 patients had 62 distal artery and vein anastomoses and 26 proximal saphenous vein-internal mammary end-to-side anastomoses. Internal mammary artery free flows ranged from 130 to 420 ml/min. Two hospital deaths were unrelated to the technique. There have been no strokes or recurrences of angina. An inordinately high incidence of main left coronary disease (50%), significant carotid disease (79%), and abdominal aortic occlusive or aneurysm disease (93%) was discovered. Ascending aortic atherosclerosis must be suspected in all coronary bypass patients with associated significant carotid, abdominal aortic, and main left coronary artery disease, aortic wall irregularity on ascending aortic angiography, adhesions between the ascending aorta and its adventitia, pale appearance of the ascending aorta, and minimal bleeding of an aortic cannulation stab wound. A "no-touch" technique that avoids any manipulation of the ascending aorta and that uses the internal mammary arteries as the sole source of blood supply for coronary bypass is an effective method to prevent aortic clamp injury, "trash heart," or stroke from severe ascending aortic disease. Preoperative angiographic visualization of the ascending aorta of all patients undergoing coronary artery bypass is mandatory.

Aged↗
PubMed1990

Newer surgical techniques in myocardial revascularization.

Recent trends in the patient population coming for surgical treatment of coronary artery disease have prompted alterations in the type of coronary artery bypass surgery performed. Emphasis is placed on the more widespread use of arterial grafts and revascularization of vessels with extensive distal disease, utilizing endarterectomy techniques, in an attempt to provide a more complete and long-lasting revascularization.

Coronary Artery Bypass↗
PubMed1989

Right gastroepiploic artery: a third arterial conduit for coronary artery bypass.

Experience with 39 patients (32 men, 7 women) undergoing coronary artery bypass grafting with the right gastroepiploic artery (RGEA) is reported. Indications initially included poor-quality or absent saphenous vein, ascending aortic atherosclerosis, and repeat coronary artery bypass grafting. The average number of grafts per patient was 4.10. Arteries bypassed were the posterior descending (22 patients), right coronary (12), diagonal (5), and marginal (4). Distal RGEA internal diameters of all grafts measured 1.5 to 3.25 mm (average diameter, 2.14 mm). Pedicled graft lengths measured 18 to 30 cm (average length, 23.7 cm), and free grafts, 8 to 24 cm (average length, 17.7 cm). In 6 patients, no vein grafts were used, and in all patients, at least one internal mammary artery graft was placed. Early postoperative cardiac catheterization (19 pedicled and ten free grafts) in 29 patients revealed all grafts to be patent without a kink or twist, but three of these free RGEA grafts had vasospasm. Advantages of RGEA grafts are as follows: (1) it is a third arterial conduit with artery-artery anastomoses of comparable sizes; (2) a shorter leg incision or no leg incision is necessary; (3) it can be harvested simultaneously with the internal mammary artery and the saphenous vein; (4) the proximal anastomosis (free grafts) is easy; (5) its use avoids bilateral internal mammary artery grafts in patients at high risk for sternal infection; and (6) atherosclerotic ascending aortas are not clamped. Subintimal hyperplasia and atherosclerosis of RGEA grafts are unlikely.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Technical considerations for use of the gastroepiploic artery for coronary artery surgery.

Disappointing long-term results with saphenous vein graft (SVG) for coronary bypass and excellent long-term results with internal mammary artery (IMA) to coronary bypass have prompted a search and research for other alternative coronary bypass conduits. Experience with the radial artery was disappointing due to early failure of those grafts. Likewise, conduits of artificial materials and homograft veins have not produced acceptable long-term results.

Arteries↗
PubMed1989

Preparation of the internal mammary artery graft. Which is the best method?

Early reports questioned the adequacy of flow of the internal mammary artery when used routinely as a bypass graft. "Adequate" mammary artery flow is now contested only in certain situations, that is, left ventricular hypertrophy, acute myocardial infarction, and reoperations. To compare the methods of mammary pedicle graft preparations with free mammary artery flow, we studied 31 patients who had the left internal mammary artery harvested for elective coronary artery bypass grafting. Group I comprised 14 patients whose mean body surface area was 1.91 m2. Systolic, diastolic, and mean arterial blood pressures, left atrial pressure, and heart rate were recorded and stabilized during flow measurements. Free flow of the internal mammary artery was measured before any pharmacologic manipulation and ranged from 5 to 44 ml/min (mean 18 ml/min). The grafts were sprayed and wrapped in sponges soaked in diluted papaverine solution (60 mg in 40 ml normal saline) for an average of 21 minutes. Free flow ranged from 10 to 108 ml/min (mean 51 ml/min). Intraluminal papaverine of the same dilution was then injected with hydrostatic dilatation. Immediate internal mammary artery flows rose from 150 to 333 ml/min (mean 229 ml/min). Group II comprised 17 patients who had internal mammary artery takedown under the exact conditions used in group I. Mean body surface area was 1.89 m2. Mammary artery pedicles were injected with diluted papaverine throughout their lengths with size 25 needles. After an average of 19.5 minutes, free flow ranged from 28 to 132 ml/min (mean 69 ml/min). Intraluminal diluted papaverine was then administered as in group I, and flows increased from 144 to 280 ml/min (mean 198 ml/min). The distal internal mammary arteries in both groups were 1.75 to 2.5 mm in internal diameter at the site of arteriotomy for flow measurement. This study shows that all mammary arteries are in spasm immediately after harvest and that flow is inadequate before any pharmacologic intervention. Although extraluminal vasodilators will increase free mammary artery flow, intraluminal papaverine followed by hydrostatic dilatation raises free flow to maximal capacity. Subsequent graft spasm has not been observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1988

Left ventricular aneurysm repair with myocardial revascularization: an analysis of 246 consecutive patients over 15 years.

From 1970 to 1985, 246 consecutive patients with left ventricular (LV) aneurysm underwent repair and concomitant myocardial revascularization at Ochsner Foundation Hospital. The overall incidence of perioperative death was 7.3%. Although the deaths were mainly cardiac related (10/18) with congestive heart failure (CHF) as the leading cause (6/10), 8 deaths were of noncardiac origin. Perioperative mortality increased significantly in patients with mitral regurgitation (MR) (22%; p = 0.0008); perioperative mortality for patients without MR was 4.8%. The overall 5-year survival was 69%. Late deaths were caused most commonly by myocardial infarction (20/32) with only 7 due to CHF. Predictors of long-term survival were related to LV function preoperatively: absence of CHF (p = 0.001); LV end-diastolic pressure less than or equal to 20 mm Hg (p = 0.03); and ejection fraction greater than or equal to 35% (p = 0.02). Factors that did not significantly affect long-term survival were type of aneurysm repair (resection or plication), morphology of left anterior descending coronary artery (occlusion or stenosis), and size of the aneurysm.

Adult↗
PubMed1987

Right ventricular failure: observations of the interrelationships affecting RV failure after aortocoronary bypass, valve surgery, and congenital heart defect repair.

Right ventricular dysfunction in adult coronary artery bypass surgery with or without ventricular aneurysm repair has not been a source of hospital mortality in our institution, whereas it persists as a cause of death not infrequently after repair of congenital heart disease and, on occasion, after valvular surgery. Although we have strong clues as to the true nature of this dichotomy, there are so many factors involved with open congenital heart repairs that the explanation is not certain. Considering the coronary anatomy, the character of right ventricular infarction, the total lack of reports of post-operative angiography, and our clinical results, we have not found sufficient evidence at this time to recommend bypass to right ventricular coronary branches. We believe that the use of a checklist of right ventricular dysfunction after congenital heart repair may result in detection of a reversible cause of right ventricular dysfunction that could be fatal.

Coronary Artery Bypass↗
PubMed1986

Techniques for management of the calcified mitral annulus.

Mitral annulus calcification is most often associated with myxomatous degeneration of the mitral valve. It is characterized by a horseshoe-shaped area of mitral annulus calcification that extends into the ventricular cavity to varying degrees. Standard suture techniques may be associated with fracture of the calcification and subsequent paravalvular leak. Seventeen patients aged 54 to 85 (mean 68.1) had mitral valve replacement using four techniques: suture through calcified annulus (3); decalcification (6); onlay patch (5); and drill technique (3). There were no hospital deaths, and one 81-year-old patient with associated coronary artery disease and ascending aortic calcification succumbed to a cerebrovascular accident three months postoperatively. The remaining patients are living and active with functional improvement. Follow-up has ranged from seven months to seven years with a mean of 4.0 years. One patient has hemodynamically insignificant mitral regurgitation after use of an onlay patch technique. No one technique could be singled out as clearly advantageous over the others from this series of patients.

Aged↗
PubMed1986

Sonographic characterization of carotid plaque: detection of hemorrhage.

By careful evaluation of the sonographic characteristics of carotid plaques, two patterns can be identified: a homogeneous pattern containing uniform echoes corresponding to dense fibrous tissue and a heterogeneous pattern containing mixed echoes and anechoic areas that represent intraplaque hemorrhage pathologically. A prospective study was conducted of 50 patients to determine the accuracy of identifying these different forms of plaque. The patients' carotid arteries were examined by a high-resolution duplex scanner before carotid endarterectomy. The plaques were evaluated carefully by vascular surgeons and pathologists for the presence of intraplaque hemorrhage. In this study, the accuracy of identifying the presence or absence of intraplaque hemorrhage with sonography was 90% (48 of 54); sensitivity, 94% (17 of 18); and specificity, 88% (27 of 31). High-resolution sonography appears to be an accurate means of identifying intraplaque hemorrhage and may ultimately be useful in identifying patients at risk for embolic disease.

Aged↗
PubMed1985

Left thoracotomy for reoperative coronary artery bypass procedures.

This paper describes our experience in performing saphenous vein bypass grafts to the circumflex coronary artery system with a left thoracotomy in 9 patients. Illustrative case reports demonstrate the spectrum of patients for whom this approach has been useful. The advantage of this technique is that it allows the surgeon to avoid the adhesions that make a redo sternotomy time-consuming and potentially dangerous when previously patent saphenous vein or internal mammary grafts are present. It is particularly useful for patients requiring grafting to the circumflex coronary artery system, especially if the patient is in relatively unstable condition and would benefit from rapid institution of cardiopulmonary bypass. The technique generally employs cannulation of the descending thoracic aorta for arterial inflow and of the main pulmonary artery for venous return. Usually the proximal end of the graft is easily placed to the left subclavian artery. Coronary anastomosis is performed on the cold (15 degrees C), fibrillating heart, and aortic cross-clamping and cardioplegic arrest have not been necessary. Venting is possible through the left atrial appendage should any rise in filling pressures occur. Saphenous vein or internal mammary artery may be used. All patients undergoing this technique have had expeditious discharge from the hospital and excellent relief of symptoms. The technique is an alternative to median sternotomy for properly selected patients.

Aged↗
PubMed1985

Technique and experience with azygos patch modified Blalock-Taussig anastomosis for congenital cyanotic heart disease.

Seventeen patients 1 day to 28 months old with congenital cyanotic heart disease underwent a modification of the Blalock-Taussig shunt. Eight were newborn infants weighing 2.6 to 4.8 kg. All infants had complex congenital heart defects that were not considered amenable to early correction. There were no early deaths and no shunt failures. Postoperative complications were restricted to prolonged intubation in 2 patients and a subcutaneous wound infection in a 14-day-old infant. Follow-up from 1 to 31 months revealed minimal cyanosis, stable hemoglobin levels, and good shunt murmurs, and there have been no upper extremity complications. There were 2 late deaths; 1 (the oldest patient) was related to medication, and the second resulted from small bowel necrosis. The concept of the azygos vein patch modified Blalock-Taussig shunt involves two factors: (1) mobilizing as much length as possible of the subclavian artery in spite of its distal small size to allow for a tension-free shunt to prevent tension on the anastomosis as growth occurs, and (2) enlarging the subclavian artery distal to the vertebral artery origin with an autologous azygos patch. During performance of a standard Blalock-Taussig shunt, a longitudinal incision is made through the pulmonary artery across the anastomosis into the upper subclavian artery. The appropriate length of harvested azygos vein is used as a patch angioplasty across the shunt. A tension-free shunt with a patulous distal portion is achieved. Pulmonary overcirculation is avoided by the limiting size of the proximal subclavian artery. Temporary occlusion of the shunt at operation resulted in an increased mean blood pressure from 6 to 18% in all infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Anastomosis↗
PubMed1984

Experience with operative transluminal balloon-catheter dilatation of the coronary arteries.

A technique is presented for hand dilatation of coronary artery segments not amenable to bypass with a balloon catheter. This technique is used in 8% of patients undergoing routine coronary artery bypass surgery. Problems with catheter design, although troublesome, have resulted in no adverse sequelae to the coronary arteries. Postoperative angiography has revealed a good result in 71% of the lesions dilated. The technique is simple, is performed under direct visualization, and has proved to be safe.

Angioplasty, Balloon↗
PubMed1984

Surgical management of diseased intracavitary coronary arteries.

An intracavitary location of a coronary artery is rare in our surgical experience with myocardial vascularization. This variant has occurred in the right coronary artery (0.09%) and in the left anterior descending coronary artery (0.2%). The location of the lesion and the pathological condition, length, and size of the coronary artery may dictate exposure of an intracavitary coronary artery for proper revascularization. More commonly, surgeons are unaware of the intracavitary position and during intramyocardial dissection of an artery will open a cardiac chamber where the vessel traverses the cavity. Problems that arise are introduction of air, difficulty in exposure due to blood and depth of position, and obstruction of the coronary artery during closure of the myotomy. We report here on 13 patients who required revascularization of intracavitary vessels (four right coronary arteries and six left anterior descending coronary arteries). The location and length of the intracavitary portion of the artery determined the surgical management. The methods used to close the cavity varied. The techniques employed were simple closure; moving the artery into an aerial position with cavitary closure behind it; anastomosis in the intracavitary position with closure of the myotomy around the graft; or selection of an alternate distal site for anastomosis. All patients treated for intracavitary arteries were successfully revascularized without major complications.

Coronary Artery Bypass↗