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Biomedical subjects

R M Mills

Publications and source records attributed to R M Mills.

At least 19 recordsLinked to original sources
PubMed1992

Endothelial dysfunction early after heart transplantation. Assessment with intravascular ultrasound and Doppler.

BACKGROUND: Allograft vasculopathy after heart transplantation is thought to represent a response to endothelial injury in the graft vessels. To assess endothelial function before the onset of anatomic disease, coronary vasomotor responses to adenosine, acetylcholine, and nitroglycerin were evaluated in transplant recipients by intravascular ultrasound imaging and Doppler flow studies. METHODS AND RESULTS: Nine patients were studied 1 year after heart transplantation. Acetylcholine provoked significant vasoconstriction to 82% of maximal coronary diameter but was associated with an increase in mean coronary blood flow from 63.1 to 204 ml/min. Coronary blood flow increased fivefold in response to adenosine, a normal response. CONCLUSIONS: The vasomotor response to acetylcholine at 1 year after heart transplantation is consistent with endothelial dysfunction in the epicardial conduit vessels. Microvascular function as judged by coronary flow reserve appears to be normal.

Acetylcholine↗
PubMed1992

Management of the patient awaiting cardiac transplantation.

The spectacular clinical success of heart transplantation (HTTX) in the cyclosporine era has engendered challenging new clinical problems that include long-term management of patients with severely compromised systolic function, preparation of potential HTTX recipients for major surgery followed by immunosuppression, and ethical and rational distribution of limited numbers of donated organs. The magnitude of these challenges may seem overwhelming. Fortunately, clinicians have the luxury of dealing with the issues involved one patient, and one step, at a time. The continued efforts of clinical investigators have clarified important management principles. There is a growing appreciation of the pivotal importance of mitral valve function in determining the response to medical therapy and long-term prognosis in this patient population. Enthusiasm for pharmacologic control of asymptomatic ventricular ectopy has waned; instead, the restoration and maintenance of normal atrial function has clearly taken precedence. In preparation for surgery, new endoscopic techniques offer great advantages. The use of high-technology support devices as "bridges to transplantation" has been re-examined in view of the relatively poorer short- and long-term prognosis of patients managed with these devices. Increasingly, the optimal scenario for HTTX entails transplantation of a severely compromised but medically stable patient. As specific therapy, HTTX today has relatively limited application to the vast majority of patients with heart failure (HF). Seventeen hundred heart transplants will do little to directly affect the 400,000 patients in the United States who each year develop symptomatic HF.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗
PubMed1991

Prior restenosis predicts restenosis after coronary angioplasty of a new significant narrowing.

To determine the influence of a history of restenosis on subsequent restenosis after percutaneous transluminal coronary angioplasty (PTCA) of a new significant narrowing, the records of 100 patients who underwent successful PTCA at another site ("new narrowing PTCA") greater than or equal to 2 months after successful initial PTCA were retrospectively reviewed. Patients were grouped according to whether initial PTCA resulted in restenosis, which was determined by angiographic follow-up greater than or equal to 3 months after initial PTCA. Patients in group 1 did not have restenosis after initial PTCA (n = 50), whereas patients in group 2 did (n = 40). All patients were followed for recurrent symptoms, with serial exercise tests, for greater than or equal to 6 months after new narrowing PTCA. Clinically suspected and angiographically confirmed restenosis occurred in 11 of 50 (22%) patients and 12 of 63 (19%) narrowings in group 1, and in 20 of 40 (50%) patients and 22 of 48 (46%) narrowings in group 2 (p less than 0.01 for patients, p less than 0.002 for narrowings). Multivariate analysis identified that prior restenosis (p less than 0.02, odds ratio 3.4), left anterior descending artery location of stenosis (p less than 0.04, odds ratio 3.0), and severity of stenosis before PTCA (p less than 0.02, odds ratio 1.8) were independently associated with restenosis after new narrowing PTCA. In conclusion, prior restenosis is an independent risk factor for subsequent restenosis after new narrowing PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1991

Outcome after major dissection during coronary angioplasty using the perfusion balloon catheter.

Coronary artery dissection is an infrequent but serious complication of coronary angioplasty that can lead to periprocedural vessel occlusion, emergency bypass surgery, myocardial infarction or death. Recently, a perfusion balloon catheter was developed that permits passive perfusion of blood through the central lumen of the catheter. It enables prolonged balloon inflations to be performed and has been used to provide distal blood flow after coronary occlusion. To evaluate the effectiveness of the perfusion balloon catheter in patients with major coronary dissections, 36 consecutive patients treated with the perfusion balloon catheter were compared with 46 consecutive patients treated before its availability. The 2 groups were similar in terms of clinical, angiographic and initial procedural characteristics. Use of the perfusion balloon catheter permitted a significantly longer inflation than standard balloon inflation (average 18 +/- 5 min). Angiographic success was significantly greater with the perfusion balloon catheter (84 vs 62% for conventional therapy), whereas complications were markedly reduced (48 vs 78%). With the perfusion balloon catheter there were fewer deaths (2 vs 6%), myocardial infarctions (14 vs 40%) and emergency bypass operations (11 vs 25%). The findings of this retrospective comparison demonstrate that the perfusion balloon catheter is effective for the management of major dissections after coronary angioplasty. The use of the perfusion balloon catheter should be considered when a major coronary dissection occurs and when emergency bypass surgery is contemplated.

Aged↗
PubMed1991

Developing a rational management strategy for angina pectoris after coronary bypass surgery: a clinical decision analysis.

Long-term follow-up of patients undergoing coronary artery bypass graft surgery indicates that as many as 50% eventually experience recurrent angina pectoris. Rational management of these individuals requires an understanding of the natural history of coronary bypass grafts, the risks and benefits of both reoperation and angioplasty, as well as a structure within which to integrate these data. This report reviews the literature and employs formal decision analysis to develop a strategy for management of recurrent angina. Our analysis supports the strategy that patients experiencing recurrent angina within 3 years after surgery should undergo prompt angiographic re-evaluation and angioplasty if anatomically suitable. Symptoms beginning more than 6 years after surgery should be managed medically, reserving surgery for refractory symptoms.

Angina Pectoris↗
PubMed1990

Clinical experience with percutaneous brachial coronary angiography in a "Judkins" laboratory.

More than 98% of coronary studies performed in our laboratory are done with the transfemoral approach. In this report, we review our experience with 67 cases in which we used the percutaneous brachial approach as an alternative for patients with peripheral vascular disease. Sixty-six cases (99%) were completed; one case (1%) was aborted due to cardiogenic shock. No death, stroke, or myocardial infarction occurred. Seven patients (10%) had minor complications; none required surgical intervention. The percutaneous brachial approach with standard preformed catheters offers a simple and satisfactory alternative to transfemoral coronary angiography.

Angiography↗
PubMed1990

Catheterization of coronary artery bypass graft from the descending aorta.

The increasing frequency of reoperation for coronary artery disease has led to the use of a variety of grafts. This report describes the catheter technique for selective opacification of a saphenous vein graft from the descending thoracic aorta to the posterior coronary circulation.

Angina Pectoris↗
PubMed1989

Effect of arginine vasopressin on coronary and systemic hemodynamics in man.

Arginine vasopressin is a potent constrictor of isolated arterial segments in vitro. However, it is disputed whether, in vivo, arginine vasopressin acts as either a systemic or coronary vasoconstrictor. The purpose of this study was to determine the effect of arginine vasopressin on coronary and systemic vascular tone in man. Six patients undergoing routine diagnostic cardiac catheterization were studied. At angiography, all patients were found to have severe coronary artery disease. Cardiac and systemic pressures and coronary blood flow as well as serum arginine vasopressin and osmolality levels were measured before and after administration of hypertonic contrast dye and then following intravenous injection of an analog inhibitor of arginine vasopressin. At baseline, serum arginine vasopressin levels were within the normal range in all patients, but, following infusion of contrast dye, rose above physiological levels in 5 patients. In these latter patients, there were no significant changes in coronary and systemic hemodynamics between baseline (condition 1), following administration of contrast dye (condition 2) and 10 minutes after injection of arginine vasopressin inhibitor (condition 3). Mean coronary sinus blood flow (ml/min) and mean coronary vascular resistance (dyne.sec.cm-5) were 184 +/- 49 and 41,235 +/- 8275 during condition 1, 204 +/- 62 and 39,442 +/- 8781 during condition 2, and 192 +/- 75 and 44,930 +/- 11455 during condition 3. Mean arterial pressure (mm Hg) and mean systemic vascular resistance (dyne.sec.cm-5) during conditions 1, 2 and 3 were 105 +/- 12 and 1454 +/- 174, 114 +/- 21 and 1432 +/- 210, and 114 +/- 15 and 1436 +/- 147, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Minimal internal and external fixation in oblique lower extremity fractures: a report of five cases and description of technique.

Interfragmentary lag screw internal fixation was combined with external fixation to treat five difficult oblique lower extremity fractures. Uncomplicated primary bone healing was achieved in all five cases in spite of crush injury, devascularization, or local infection. This method represents a treatment option for the difficult oblique fracture and reconfirms the role of fixation in fracture biology.

Adult↗
PubMed1988

Ischemic stroke after cardiac pacemaker implantation in sick sinus syndrome.

The risk of embolic stroke during sick sinus syndrome before cardiac pacemaker insertion is substantial, but stroke after pacemaker insertion has not been well studied. We observed 10 sick sinus syndrome patients who developed an ischemic stroke 4 days to 112 months after pacemaker insertion. Nine patients represented 6% of the 156 ischemic stroke patients observed during a 30-month period. Eight had a ventricular-demand pacemaker, one had a dual-chamber pacemaker, and one had an atrial-inhibited pacemaker. Six patients were in atrial fibrillation at stroke onset, but none had atrial fibrillation when the pacemaker was inserted. Six patients were taking aspirin, and one was anticoagulated when stroke occurred. Stroke in sick sinus syndrome after pacemaker insertion is not rare, and pacing does not appear to be protective. Sick sinus syndrome patients who convert to atrial fibrillation or who have a ventricular-demand pacemaker might represent high-risk groups for stroke.

Aged↗
PubMed1979

Sustained effect of orally administered isosorbide dinitrate on exercise performance of patients with angina pectoris.

The efficacy of oral isosorbide dinitrate was evaluated in nine hospitalized patients with chronic angina pectoris and positive maximal bicycle exercise tests. Patients were randomized double-blind to receive either 20 mg of isosorbide dinitrate or placebo on successive days after a control maximal upright bicycle exercise test. On each day hourly exercise tests were performed for 4 hours after drug administration to an end point of fatigue or angina pectoris. Mean systolic blood pressure 4 hours after the administration of isosorbide dinitrate was 25 mm Hg less than the control value (P less than 0.001). The values for resting heart rate and exercise-attained heart rate-blood pressure product were not significantly different from the values after placebo. The duration of exercise was prolonged (P less than 0.025) for at least 3 hours, and less ST depression (P less than 0.01) was observed up to 3 hours after the administration of isosorbide dinitrate compared with control values. The demonstration of sustained imporved exercise performance and previously described hemodynamic effects with the use of higher doses suggests that adequate blood levels of isosorbide dinitrate or mononitrate metabolites may be important for the efficacy of oral organic nitrates.

Administration, Oral↗
PubMed1977

Severe bronchial asthma: factors influencing intensive care management and outcome.

Over a seven year period 2933 patients were admitted with asthma. Respiratory failure occurred on 106 occasions. A total of 26 patients died including 11 of the 106 who developed respiratory failure. The intra-hospital management of asthma is outlined. The experience is analysed to indicate those patients particularly at risk. These include those who develop pneumothorax, have associated chest infections or have recently ceased steroid therapy.

Adolescent↗
PubMed1977

Acute respiratory failure in a regional respiratory unit.

One thousand, six hundred and sixteen patients with acute respiratory failure were managed in a regional respiratory unit. The patients are classified according to cause, the need for artificial ventilation and results.

Acute Disease↗
PubMed1976

Reflex increase in coronary vascular resistance in patients with ischemic heart disease.

To assess possible coronary vasoconstriction in patients with ischemic heart disease, we measured coronary vascular resistance in 12 patients with normal hearts and 12 with coronary disease before and during the initial 50 seconds of cold pressor test, a stimulus known to produce systemic vasoconstriction. Control coronary vascular resistance was similar in the two groups, and although it did not change in patients with normal vessels, it rose by 27 per cent (P less than 0.005) in the group with coronary disease during the cold pressor test. In three of 12 patients with coronary disease coronary flow actually declined despite an increase in arterial pressure; in four, angina was precipitated. Phentolamine abolished increases in arterial pressure and coronary vascular resistance during the test in three patients with coronary disease. Adrenergically mediated coronary vascular tone may be an important determinant of coronary blood flow and may contribute to ischemia in patients with coronary disease.

Adrenergic alpha-Antagonists↗