Long-bone fractures in llamas: six cases (1993-1998)

OBJECTIVE

To determine clinical and radiographic findings, treatment, and outcome for llamas with long-bone fractures.

DESIGN

Retrospective study.

ANIMALS

6 llamas.

PROCEDURE

Medical records of llamas admitted between 1993 and 1998 because of long-bone fractures were reviewed. Data collected included age, sex, type of fracture, method of fracture repair, and postoperative complications. The Fisher exact test was used to compare age and sex of the llamas with long-bone fractures with those of the hospital population of llamas. All owners were contacted by telephone to determine perceived postoperative problems and whether the llamas were able to perform as expected.

RESULTS

Mean age was 160.8 days (range, 23 to 365 days). There was 1 male and 5 females. Fractures were more likely to occur in young llamas (< or = 1 year old) than in adults. Five of the fractures were attributed to traumatic episodes. Long bones affected included the tibia (n = 2), radius (2), femur (1), and humerus (1). Internal fixation with lag screws, plating, or both was performed on fractures of all llamas except 1; that llama was treated by use of confinement to a stall. None of the llamas had intraoperative complications, but postoperative complications were reported in 2 llamas. All fractures healed eventually, and clients were pleased with outcomes.

CONCLUSIONS AND CLINICAL RELEVANCE

Long-bone fractures in llamas are uncommon. Several types of long bone fractures can be successfully repaired by use of internal fixation, resulting in few complications and minimal convalescent time.

Low-field magnetic resonance imaging of the equine tarsus: normal anatomy

The objective of this study was to define the normal gross anatomic appearance of the adult equine tarsus on a low-field magnetic resonance (MR) image. Six radiographically normal, adult, equine tarsal cadavers were utilized. Using a scanner with a 0.064 Tesla magnet, images were acquired in the sagittal, transverse and dorsal planes for T1-weighted and the sagittal plane for T2-weighted imaging sequences. Anatomic structures on the MR images were identified and compared with cryosections of the imaged limbs. Optimal image planes were identified for the evaluation of articular cartilage, subchondral bone, flexor and extensor tendons, tarsal ligaments, and synovial structures. MR images provide a thorough evaluation of the anatomic relationships of the structures of the equine tarsus.

Effect of hydration on signal intensity of gelatin phantoms using low-field magnetic resonance imaging: possible application in osteoarthritis

Five gelatin phantoms were constructed to study the effect of matrical hydration on magnetic resonance imaging (MRI) signal intensity using a low-field strength imager. Water content of the phantoms ranged from 75 to 95% weight/weight. Signal intensity values of each phantom were measured using five imaging sequences: proton density, T1-weighted, T2-weighted, inversion recovery with short inversion time, and inversion recovery with long inversion time. There was significant positive correlation (p < .05) of signal intensity with differences in hydration using the T2-weighted sequence and the inversion recovery sequence with short inversion time. Significant negative correlations (p < .05) were found with T1-weighted imaging and the inversion recovery sequence with long inversion time. In a second part of the study, in vivo focal variations in MRI signal intensity were evaluated in a canine cranial cruciate ligament deficient model of osteoarthritis. Signal intensity measurements were obtained from multiple areas of articular cartilage to identify an initial stage in osteoarthritis that is characterized in part by increased hydration of articular cartilage. At 6 weeks post-transection of the cranial cruciate ligament, an increase in signal intensity was detected in the articular cartilage of the weight-bearing portion of the lateral femoral condyle and the caudal portion of the medial tibial condyle with T1-weighted imaging. The increase in signal intensity may reflect increased proteoglycan synthesis by chondrocytes that also occurs early in the pathogenesis of osteoarthritis.

Lethal postoperative coronary artery spasm

BACKGROUND

Coronary artery spasm in the immediate postoperative period after a coronary operation is recognized infrequently. Its severity is variable and manifestations unpredictable. The diagnosis is usually made by an awareness of the possibility and thereafter by exclusion of other causes of myocardial ischemia. An opportunity for a positive diagnosis is rarely available.

METHODS

The case reports of 3 patients with similar presentations of ischemic heart disease and with severe manifestations of coronary artery spasm in the postoperative period are presented.

RESULTS

All 3 patients were women aged 55 to 60 years. All had single-vessel coronary artery disease involving the left anterior descending artery and underwent a left internal mammary artery bypass graft. Severe manifestations of myocardial ischemia of abrupt onset developed approximately 7 hours postoperatively in each patient. One patient died of severe hemodynamic deterioration from which resuscitation was unsuccessful. Another sustained a large anterior myocardial infarction despite graft patency. The third patient was supported by an intraaortic balloon pump and made a full recovery.

CONCLUSIONS

The early diagnosis of coronary artery spasm is achieved by an awareness of the condition. The institution of early appropriate management may prevent its consequences.

Low-field magnetic resonance imaging of early subchondral cyst-like lesions in induced cranial cruciate ligament deficient dogs

Six healthy adult male mongrel dogs underwent cranial cruciate ligament transection in the left stifle. Survey radiography of both stifles and low-field (0.064 T) MRI of the left stifle were performed preoperatively and at 2, 6, and 12 weeks postoperatively. Focal changes in signal intensity were seen with MRI in the subchondral bone of the medial tibial condyle at 2 and 6 weeks postoperatively. At 12 weeks postoperative, a cyst-like lesion was detected using MRI in the subchondral bone of the medial tibial condyle in 4 of 6 dogs and a less defined lesion at this site in the remaining 2 dogs. The cyst-like lesion was spherical in shape and showed typical characteristics of fluid with low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and high signal intensity on inversion recovery images. The lesion was seen in the subchondral bone of the caudal medial and/or middle region of the tibial plateau slightly cranial to the insertion of the caudal cruciate ligament. No subchondral cysts were seen in the tibia on radiographs. Histopathologically, the tibia was characterized by a loose myxomatous phase of early subchondral cyst formation.

Low-field magnetic resonance imaging of the canine stifle joint: normal anatomy

Low-field magnetic resonance imaging (MRI) was performed on the stifle joints of four normal adult mongrel dogs using a 0.064 Tesla scanner. Markers were placed on each stifle joint to serve as reference points for comparing gross sections with the images. A T1-weighted sequence was used to image one stifle joint on each dog in the sagittal plane and the other stifle joint in the dorsal plane. The dogs were euthanized immediately following MRI and the stifle joints frozen intact. Each stifle joint was then embedded in paraffin, again frozen, and sectioned using the markers as reference points. On T1-weighted images, synovial fluid had low signal intensity (dark) compared to the infrapatellar fat pad which had a high signal intensity (bright). Articular cartilage was visualized as an intermediate bright signal and was separated from trabecular bone by a dark line representing subchondral bone. Menisci, fibrous joint capsule, and ligamentous structures appeared dark. In the true sagittal plane, the entire caudal cruciate ligament was often seen within one image slice. The patella was visualized as an intermediate bright signal (trabecular bone) surrounded by a low intensity signal (cortical bone). The trochlea and the intercondylar notch were difficult areas to analyze due to signal volume averaging of the curved surface of these areas and the presence of several types of tissues.

Ameloblastic fibrosarcoma in a bull

This report describes a malignant odontogenic neoplasm in a 7-year-old bull. The mass, involving the right mandible, was locally invasive and destructive. Histologically, it consisted of islands and cords of benign odontogenic epithelium, entrapped in a population of malignant mesenchymal cells. These morphological features are characteristic of ameloblastic fibrosarcoma in man, an odontogenic tumour not previously described in animals.

Morphology of the musculus articularis genus in dog with description of ectopic muscle spindles

The gross morphology of the musculus articularis genus and the location of muscle spindles at its point of insertion were studied in 18 adult dogs. The m. articularis genus was usually small and bipartite. From its originate on the cranial surface of the distal femur, it passed distally to terminate at the femoropatellar-joint capsule surface and extend into the synovial membrane. Although the m. articularis genus was usually composed of two parts, only a medial part was present in some dogs and was entirely absent in one specimen. Innervation to the m. articularis genus was provided by a branch of the femoral nerve. Muscle spindles were abundant in the termination of the muscle. spindles were abundant in the termination of the muscle. Frequently, the spindles were not in contact with muscle fibers (dissociated). Muscle spindles were located in close proximity to the surface of the synovial membrane. Morphological adaptations of the m. articularis genus support its potential function as a monitor of joint movement rather than an extensor of the stifle joint.

Tumor necrosis factor-alpha (TNF-alpha) in canine osteoarthritis: Immunolocalization of TNF-alpha, stromelysin and TNF receptors in canine osteoarthritic cartilage

The presence and distribution of tumor necrosis factor-alpha (TNF-alpha), TNF receptors and stromelysin [matrix metalloproteinase 3 (MMP-3)] in articular cartilage were evaluated in an iatrogenically induced model of osteoarthritis (OA). Eleven adult male dogs were assigned randomly to a control group (N = 4) or an OA group (N = 7). Osteoarthritis was created by surgical transection of the cranial cruciate ligament of one stifle joint. Both femoral condyles were sampled 3 months post-surgery at necropsy and immunohistochemically analyzed for the presence of the aforementioned cytokines and receptors. Chondrocytes stained for TNF-alpha and TNF receptors in control articular cartilage, spanning an area encompassing most of the middle and deep zones. Positive matrical and chondrocytic staining for TNF-alpha, TNF receptors, and stromelysin was present in OA articular cartilage. Staining varied in intensity and distribution and was dependent of the severity of the lesion. Smooth muscle cells of arteries and arterioles (periarticular synovial membrane) were stained for only one (p55) of two TNF receptors; this staining was confined to control tissues. Results indicate that the differential expression of TNF-alpha and its receptors may be important in the normal maintenance of articular cartilage. The increased presence of TNF-alpha and its receptors in articular cartilage with mild osteoarthritic changes suggests a role in the development of early OA. Regulating TNF-alpha may be an important component in the treatment of OA.

Redistribution of vertical ground reaction force in dogs with experimentally induced chronic hindlimb lameness

When lameness occurs in a load-bearing limb, compensatory load adjustments are made in the other supporting limbs. The vertical component of the ground reaction force, as measured by force platform analysis, reflects these adjustments. This study describes the pattern of vertical ground reaction force redistribution during experimental, chronic hindlimb lameness in dogs. The peak and impulse of the vertical ground reaction force were measured and described in 13 dogs before, and at 2, 6, and 12 weeks after transection of the cranial cruciate ligament. These variables were compared among limbs. The vertical ground reaction force in the forelimbs did not change significantly during the course of the study. At 2, 6, and 12 weeks after surgery, means of peak vertical force in the limb that underwent surgery were 18.9%, 44.0%, and 61.3% respectively, of presurgical values. In the contralateral limb, corresponding values were 131.7%, 112.8% and 112.9% respectively. If one accepts the relationship of mechanical loading to musculoskeletal architecture and the now certain relationship between lameness and compensatory loading of other limbs, then the use of another limb of the same animal as a control is a potential study design flaw.

Upper gastrointestinal haemorrhage following coronary artery bypass grafting

BACKGROUND

Upper gastrointestinal (UGI) bleeding is a relatively common and potentially fatal complication of coronary artery bypass graft (CABG) surgery. However, little is known of this problem, including its incidence, predisposing factors and safety of endoscopy in these patients.

AIM

To document the incidence, site, predisposing factors and outcome of UGI bleeding following CABG surgery. Also, to assess the safety of UGI endoscopy in these patients.

METHOD

Retrospective study of UGI haemorrhage following CABG at one institution between 1976 and 1991.

RESULTS

Fifty-five of 10,573 patients (0.5%) suffered a major UGI haemorrhage (as defined by need for transfusion or presence of melaena or haematemesis associated with hypotension). Of 51 patients undergoing endoscopy or laparotomy, 42 (82%) bled from duodenal ulceration. Five patients bled from gastric ulcers and one each from oesophagitis and Mallory Weiss tear. Nine patients underwent endoscopic therapy, which initially arrested haemorrhage in eight patients. However, three patients rebled and required surgery. Eight patients underwent surgery as initial therapy, resulting in an overall surgical rate of 20%. One patient died due to multi system failure following surgery. There were no complications from endoscopy. Patients who bled were more likely to have received inotropic support post-operatively prior to the haemorrhage (p < 0.05) and tended to be older than controls (mean age 65.6 years vs 58.7 years, p < 0.01). Twenty-one of the patients (38%) who bled had a past history of peptic ulceration or dyspepsia compared with 9% of controls (p < 0.001). Seven (12.5%) had previously bled from peptic ulceration. Patients who bled were less likely to have received H2-receptor antagonists in the perioperative period than controls (4% vs 20%, p < 0.05).

CONCLUSION

Upper GI haemorrhage following CABG is relatively frequent. It is usually secondary to duodenal ulceration. Endoscopy is a safe procedure in this patient group. Mortality did not differ between index patients who suffered a UGI haemorrhage and controls undergoing CABG who did not bleed.

Video-assisted thoracoscopy

Recent advances in video-imaging and minimally invasive surgical instrumentation have expanded the role of thoracoscopy in the diagnosis and treatment of intrathoracic conditions. This prospective study describes the use of video-assisted thoracoscopy (VAT) in 100 consecutive patients. There were 70 males and 30 females with a mean age of 54.6. They underwent 103 VAT procedures with 41 thoracoscopic biopsies of lung, pleural, chest wall and mediastinal abnormalities, 32 for treatment of recurrent or persistent pneumothorax, 18 for thoracoscopic assessment of pulmonary and pleural tumours and 12 for thoracoscopic resection of peripheral lung lesions, chest wall, mediastinal and pleural tumours. Eighty-one patients had VAT procedures alone while the remaining 19 had VAT proceeding to thoracotomy. The mean operating time for VAT alone was 51 min (range 30-135 min). There were no operative deaths. There were 8 significant complications from which patients recovered fully. Patients who underwent VAT alone were shown to have earlier postoperative mobilization, reduction in parenteral analgesic requirement and reduced length of hospital stay compared to patients undergoing additional thoracotomy. A telephone survey of patients on returning home showed that patients undergoing VAT alone returned to full activity earlier than those who had thoracotomy (mean 9.0 vs mean 19.4 days). This study confirms that VAT is a safe and effective procedure in the management of pulmonary, mediastinal and pleural disease and the treatment of persistent and recurrent pneumothorax. Its role in the resection of pulmonary malignancy remains to be defined.

Ground reaction force profiles from force platform gait analyses of clinically normal mesomorphic dogs at the trot

Force platform analysis of gait provides ground reaction force information that can be used to study limbs with normal or abnormal function. When combined, the interrelated variables of ground reaction forces give a more thorough description of gait than when used individually. To describe the pattern of ground reaction forces in clinically normal, conditioned, mesomorphic dogs, we studied the data from platform gait analyses of 43 dogs. Mediolateral (Fx), craniocaudal (Fy), and vertical (Fz) forces were measured and recorded. Torque (Tz) around the vertical axis also was calculated. Mean stance times for forelimbs and hind limbs were 0.278 and 0.261 second, respectively. Among dogs, ground reaction forces were normalized and expressed as percentage of body weight (%bw). The vertical (Fz) peak, average force during stance phase, and force vs time impulses were 106.68, 60.82, and 17.2 %bw in forelimbs, and were 65.11, 35.3, and 9.33 %bw in hind limbs. The forelimb braking/propulsive (Fy) peaks were -16.74 and +6.73 %bw. In hind limbs, these peaks were -3.76 and +7.69 %bw. The usual mediolateral force (Fx) pattern found in forelimbs was laterally directed, with average peak magnitude of 6.69 %bw, whereas the hind limb patterns were variable.

Vertical ground reaction force distribution during experimentally induced acute synovitis in dogs

The pattern of vertical ground reaction force redistribution among limbs during episodes of acute synovitis of the stifle in 12 mixed-breed dogs was investigated as an adjunct to a blinded nonsteroidal anti-inflammatory drug efficacy study. Without regard to drug efficacy groupings, the redistribution of vertical forces before and during the acute synovitis episode was evaluated by analysis of gait, using a force platform. Acute synovitis was induced by intrasynovial injection of sodium urate crystals. Simultaneously, each dog was given 1 of 4 treatment regimens, including IV injection of sterile saline solution (as a negative control), phenylbutazone (as a positive control), or 1 of 2 proprietary nonsteroidal anti-inflammatory drugs. Postinjection analyses took place at 2, 4, 8, 12, 24, and 36 hours. The peak vertical force redistribution in the 3 untreated limbs of the dogs was described. The greatest redistribution was observed 4 hours after substance injection when the synovitis was clinically at maximum. Thereafter, there was steady improvement and the dogs had a clinically normal gait 24 hours after substance injection. During synovitis, peak vertical force increased in the contralateral hind limb. During the more severe synovitis episodes, force was decreased in both forelimbs. There was good correlation between severity of lameness and peak vertical force response in the contralateral hind limb. Results of the study indicate that the untreated limbs of the same animal should not be used as a control during acute lameness studies.

Predominant alpha 1-adrenoceptor-mediated contraction in the human internal mammary artery

alpha-Adrenoceptor agonists and antagonists are widely used perioperatively for internal mammary artery (IMA)-coronary artery bypass operations. To determine subtypes of alpha-adrenoceptors in the human IMA, we studied responses of isolated human IMA segments to alpha-adrenoceptor agonists, antagonists, and electrical stimulation in organ baths. The IMA ring segments (3 mm long) were set up at a physiologic and comparable condition according to their own length-tension curves. alpha 1-Agonist methoxamine (MO) induced 2.65 +/- 0.70 g force and alpha 1, alpha 2-agonist norepinephrine (NE) induced 4.07 +/- 0.70 g force. The contractions induced by both MO and NE were totally abolished by alpha 1-antagonist prazosin (0.1 microM) but not alpha 2-antagonist yohimbine. alpha 2-Agonist UK14304 induced only 0.39 +/- 0.17 g force, which was significantly less than that induced by MO or NE (p < 0.001). Contractions induced by electrical field stimulation (2, 10, 20 Hz) were decreased by alpha 1-antagonist prazosin 1 microM (p < 0.01) but potentiated by alpha 2-antagonist yohimbine. These results strongly suggest that in the human IMA the postjunctional alpha-adrenoceptors are predominantly of the alpha 1-subtype and therefore the alpha-adrenoceptor agonist-induced contraction and the sympathetic nerve stimulation-induced contraction is mediated mainly by activation of the alpha 1-adrenoceptors.

Inhibitory effects of glyceryl trinitrate on alpha-adrenoceptor mediated contraction in the human internal mammary artery

1. Sympathomimetic amines have been considered to be related to vasospasm. Previous studies showed that the human internal mammary artery (IMA) was capable of weak beta-adrenoceptor mediated relaxation and that alpha-adrenoceptor agonists may induce contraction in the human IMA. 2. We investigated the effects of glyceryl trinitrate (GTN), a vasodilator agent often used perioperatively, on alpha-adrenoceptor mediated contraction in the human IMA. 3. Discarded human IMA segments were taken from 37 patients who underwent IMA--coronary artery bypass graft operations and equilibrated in an organ bath. 4. A specially designed technique was used to normalize the vessel segments under the pressure similar to the in vivo situation. Noradrenaline (NA), phenylephrine (PE), and methoxamine (MO) were used to contract the vessel segments. 5. GTN fully relaxed PE or MO (submaximal concentration) induced precontraction. Therapeutic plasma concentration of GTN relaxed 40-90% of the PE induced contraction (2.82 g, EC50 = 7.92 +/- 0.06 -log M) and 20-90% of the MO induced contraction (1.8 g, EC50 = 7.63 +/- 0.16 -log M). Pretreatment by the therapeutic plasma concentration of GTN inhibited the contraction induced by NA, PE in a different range. It reduced the NA induced contraction (6.9 g) by 14.8-38% (P greater than 0.05) and the PE induced contraction (4.3 g) by 7.9-39.3% (P greater than 0.05). The alpha 1-adrenoceptor antagonist prazosin, at the therapeutic plasma concentration, nearly totally abolished the NA or PE induced contraction (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Persistent ductus arteriosus in adults. A review of surgical experience with 25 patients

OBJECTIVE

To review the clinical features, operative details and course of adults with persistent ductus arteriosus.

DESIGN

Retrospective study. Information on subjects was obtained by case records review.

SETTING

The Cardiothoracic Unit, Royal Prince Alfred Hospital, Sydney.

PATIENTS

Twenty-five adults aged 16 years and over with persistent ductus arteriosus, from 1974-1990.

INTERVENTION

Surgical division or ligation of persistent ductus, via left thoracotomy or median sternotomy.

MAIN OUTCOME MEASURES

Preoperative clinical features; postoperative mortality and morbidity.

RESULTS

There was a high incidence of symptoms in this group of adults with persistent ductus arteriosus, many having anatomical (aneurysm, calcification) and/or haemodynamic (heart failure, pulmonary hypertension) complications. There was one death (mortality, 4%) of a young woman with significant preoperative pulmonary hypertension. The remaining 24 patients (96%) left hospital completely well between 4 and 12 days after surgery.

CONCLUSIONS

Persistent ductus arteriosus, although primarily a paediatric problem, may present in adulthood. Closure by operative means (or in selected cases, by interventional catheter) is warranted in all adult subjects with left to right shunt, other than for patients over 60 years of age with neither heart failure nor cardiomegaly.

Mitral valve replacement combined with coronary artery operation: determinants of early and late results

Mitral valve replacement combined with coronary artery bypass grafting has been reported as being associated with a higher mortality than either mitral valve replacement or coronary artery bypass grafting alone. Cause of mitral valve disease and severity of mitral regurgitation have been reported as related to mortality. To study the correlation of the cause of mitral valve disease and severity of mitral regurgitation to hospital mortality and long-term survival, we analyzed the results of 135 patients undergoing mitral valve replacement and coronary artery bypass grafting between June 1974 and August 1989. The hospital mortality was 11.8% (16/135). Fifteen preoperative and operative variables were tested for correlation with hospital or late mortality using univariate tests and multivariate regression. Advanced age (greater than 60 years), New York Heart Association functional class, and wall motion score were independently associated with hospital mortality (p less than 0.05). The cause of mitral valve disease and severity of mitral regurgitation were not related to hospital mortality or long-term survival (p greater than 0.05). The follow-up rate was 96.6% for the hospital survivors (115/119). Mean follow-up was 52.6 +/- 4.1 months. There were 35 late deaths. Survival was 91.9%, 89.9%, 78%, and 49.9% at 1, 2, 5, and 10 postoperative years, respectively. Preoperative New York Heart Association functional class and use of catecholamines during the postoperative intensive care period were independently related to late survival (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The importance of age as a predictor of atrial fibrillation and flutter after coronary artery bypass grafting

The purpose of this study was to identify factors associated with atrial fibrillation and flutter after coronary artery bypass grafting. The study group consisted of a consecutive series of 5807 patients who underwent coronary artery bypass grafting alone and who were in sinus rhythm preoperatively. Atrial fibrillation and flutter were identified during continuous monitoring or by clinical symptoms and signs; they occurred in 17.2% of the patients. The prevalence of atrial fibrillation and flutter was directly related to age at operation, varying from 3.7% in patients aged less than 40 years to 27.7% in patients aged 70 and over. In a multivariate analysis, age remained the most important independent predictor of atrial fibrillation and flutter (p less than 0.001). Other independent predictors of atrial fibrillation and flutter were chronic airflow limitation (p = 0.006), preoperative beta-adrenergic blockers (p = 0.011), and chronic renal failure (p = 0.04). Extent of coronary disease at catheterization, history of a previous myocardial infarction, heart size on chest x-ray film, and all operative factors measured, apart from year of operation, were unassociated with atrial fibrillation and flutter. Thus atrial arrhythmias after coronary artery bypass operations are most strongly related to advanced age and are unassociated with preoperative left ventricular function and extent of coronary disease.

Total intracardiac repair for tetralogy of Fallot in adults

The anatomic and clinical features of 47 patients who were 18 years of age or older at the time of total intracardiac repair for tetralogy of Fallot are reviewed. Twenty (43%) patients had had previous palliative surgery. Of 14 pulmonary-systemic shunts, 9 (64%) remained patent. The location of the ventricular septal defect was infracristal in 90% of patients. The predominant right ventricular outflow tract obstruction was at the infundibulum in 30%; another 64% of patients had combined valvular and infundibular obstruction. Total intracardiac repair was achieved; hospital mortality was 8.5%. Morbidity was minor, and hemorrhage was a significant problem in only 2 patients. Thirty-five patients have been followed from 11 months to 15 years after surgery. There were 4 late deaths; the actuarial 10-year survival rate was 82%.

Cardioplegic solution: a contamination crisis

Eleven patients were given varying doses of cardioplegic solution contaminated with Enterobacter cloacae. Five patients died. Early bleeding, necessitating reoperation, occurred in eight patients and a total of 126 units of blood and 203 units of platelets were given (range 2 to 19 and 15 to 47 units, respectively). Mycotic aneurysms developed in four patients, rupturing between the ninth and eleventh postoperative day. Only one of these patients survived. Other complications included adult respiratory distress syndrome (three patients), renal failure (four patients), sternal infections (six patients), and organic brain syndrome (five patients). Although some factors of gram-negative septicemia were identified in retrospect, others were masked by the clinical setting in which it occurred. We recommend that each dose of cardioplegic solution be prepared on an individual basis and used immediately. We also recommend that "sternal blood" be cultured on all patients. The subtle features of "gram-negative septicemia" necessitate urgent investigation and treatment. The combination of low white cell count, high cardiac output, and low peripheral vascular resistance should be assumed to indicate septicemia until proved otherwise. A full coagulation screen including platelet function and fibrin degradation products should be performed in any and all patients with these findings. Mycotic aneurysms mandate urgent reoperation with interposition of a saphenous vein segment of these patients are to survive.

Coronary artery surgery in Australia. Report from the Committee of the National Heart Foundation Coronary Artery Surgery Register

Clinical data on all patients who have undergone coronary artery surgery in Australia are collected, audited, and published each year by the National Heart Foundation of Australia. These data from 1971 to 1980 are summarized and show the indications for operation, the variation in numbers of patients operated on in each state and unit, and the overall increase in number of operations during the decade.

Influence of heart rate and atrial transport on left ventricular volume and function: relation to hemodynamic changes produced by supraventricular arrhythmia

The response of the left ventricle to pacing-induced changes in heart rate and the atrioventricular (A-V) relation was examined with equilibrium gated radionuclide ventriculography in 20 patients who had normal ventricular function after surgery for recurrent supraventricular tachycardia. In 10 patients count-derived left ventricular ejection fraction, end-diastolic volume and stroke volume were measured during sinus rhythm and during atrial pacing at 120, 140 and 160 beats/min. In the other 10 patients similar determinations were made during sequential A-V and simultaneous ventricular and atrial (V/A) pacing, both at rates of 100 and 160 beats/min. Left ventricular ejection fraction did not change significantly with atrial pacing (from 0.65 +/- 0.02 [mean +/- standard error of the mean] at a baseline sinus rate of 91 +/- 3 beats/min to 0.62 +/- 0.03 at 160 beats/min) despite a progressive decrease in end-diastolic volume. The percent reduction in end-diastolic volume (% delta EDV) and stroke volume (+ delta SV) from the baseline values was linear and related to change in heart rate (delta HR) as % delta EDV = -0.60 delta HR + 5.19 (r = 0.71; p less than 0.01) and % delta SV = -0.62 delta HR + 5.03 (r = 0.76; p less than 0.001). Left ventricular ejection fraction with baseline sequential A-V pacing at 100 beats/min was 0.67 +/- 0.03 and not significantly altered by either sequential A-V or simultaneous V/A pacing at 160 beats/min. At 100 beats/min, loss of atrial transport with simultaneous V/A pacing resulted in a small reduction in end-diastolic volume from a baseline value of -9.0 +/- 1.9 percent (p less than 0.01) and a nonsignificant reduction in stroke volume of -3.7 +/- 1.6 percent. During simultaneous V/A pacing at 160 beats/min, the reduction in end-diastolic and stroke volumes from the baseline value was -26.6 +/- 3.8 percent and -28.8 +/- 4.3 percent, respectively (both p less than 0.01), but was significantly smaller (-16.1 +/- 3.6 percent and -19.2 +/- 4.1 percent, respectively [p less than 0.05]) when atrial transport was maintained during sequential A-V pacing at the same heart rate. During simultaneous V/A pacing at 160 beats/min, two thirds of the reduction in end-diastolic and stroke volumes from the baseline value was due to the increment in heart rate as assessed from sequential A-V pacing and the other third was due to loss of atrial transport. The data indicate that the hemodynamic consequences of supraventricular tachyarrhythmias in patients with normal ventricular function are due primarily to decreases in ventricular volume as heart rate is increased and atrial contribution is lost rather than to any changes in left ventricular ejection fraction.

Pseudoaneurysm of the left ventricle

A case study is reported of a patient with rheumatoid arthritis who developed a pseudoaneurysm of the left ventricle after inferior myocardial infarction. The clinical diagnosis was confirmed by radionuclide cardiac blood pool imaging and by contrast ventriculography; the aneurysm was successfully excised.

Aortic and mitral valve replacement in a patient with severe haemophilia A

A forty-nine year old man with severe Haemophilia A developed left ventricular failure as a complication of valvular heart disease. On November 26th, 1979, open heart surgery was performed and both the aortic and mitral valves were replaced with porcine heterografts. Replacement therapy in the form of Factor VIII concentrates maintained the Factor VIII coagulant level at 100% until ten days post-operatively and a total dose of 116,600 units were given. The patient described is the first haemophiliac to undergo open heart surgery in Australia and the first reported case in the world to have had a successful double valve graft. With the current availability of factor VIII concentrates, elective surgical procedures are being performed more frequently. Such procedures require careful pre-operative planning and post-operative monitoring of replacement therapy to ensure satisfactory haemostasis. Although haemostatic defects may occur after open heart surgery, this case report illustrates that the haemostatic problems of open heart surgery and haemophilia can be prevented by pre-operative planning and meticulous post-operative monitoring of replacement therapy.

Preoperative and postoperative technetium-99m pyrophosphate myocardial scintigraphy in the assessment of operative infarction in coronary artery surgery

The incidence of operative myocardial infarction was assessed by electrocardiogram (ECG) and technetium-99m pyrophosphate (99mTc-PyP) myocardial scintigrams in 89 consecutive patients undergoing coronary artery bypass grafting (CABG). Myocardial scintigrams were performed on the day before operation and repeated 2 to 3 days postoperatively. All patients survived operation, with three in-hospital deaths not related to myocardial infarction (mortality rate 3 percent). Operative infarction was assessed to have occurred in four of 89 patients (4 percent). Two had new Q waves and positive scintigrams; one, major ST-T wave changes and a positive scintigram; and the fourth, new Q waves without a positive scintigram. Three further patients (3 percent) had Q waves and positive scintigrams postoperatively, but myocardial infarction was evolving before anesthesia and operation. Twenty-seven of 89 patients (30 percent) were found to have abnormal scintigrams preoperatively. In two patients, both operated upon with evolving myocardial infarction, the scintigram was worse postoperatively. In 13 patients the scintigram was improved after operation. In 12 patients (13 percent) the abnormal preoperative scintigram was unchanged after operation. Preoperative and postoperative myocardial scintigrams and ECG's must be compared to assess the incidence of operative myocardial infarction in patients undergoing CABG.

Coronary bypass grafting in early stages of acute myocardial infarction

Acute coronary bypass surgery was performed in four patients with early anterior myocardial infarction due to severe proximal stenosis of the left anterior descending artery. Improvemnet of left ventricular anteroapical wall contraction was detected at the completion of the operation, in the early postoperative phase, and six to 18 months after surgery. It is concluded that critically ischaemic myocardium was salvaged by revascularization.

Surgical division of an accessory atrioventricular connection in the posterior septal region following ventricular fibrillation in the Wolff-Parkinson-White syndrome

A young man presented with atrial fibrillation and a rapid ventricular response which degenerated into ventricular fibrillation. Electrophysiological study demonstrated an accessory atrioventricular connection in the posterior septal region. This was sectioned to prevent recurrence of his arrhythmia. Post-operative electrophysiological study demonstrated that the surgical section was successful.

Radionuclide imaging to assess myocardial damage during open heart surgery

Technetium 99m Pyrophosphate imaging before and after open heart surgery was performed in 38 patients to estimate the incidence of peri-operative infarction. Positive images were present pre-operatively in 11 of 30 patients with coronary artery disease. In three patients the images changed from negative to positive and in two this was thought to be due to infarction produced at operation. The high incidence of positive pre-operative images emphasises that many patients with evolving myocardial infarction, unstable angina or severe heart failure are now operated upon without delay. Because many patients have positive images before surgery pre-operative and post-operative images must be compared to assess myocardial damage due to surgery.

Surgical management of large bronchial collateral arteries with pulmonary stenosis or atresia

Single or multiple large bronchial collateral arteries may provide all or some of the pulmonary arterial blood flow in patients with proximal atresia of the pulmonary artery, and even in patients with only pulmonary stenosis. At the time of corrective surgery such arteries must be ligated in order to provide favorable operating conditions, to avoid cardiac overdistention during repair, and to prevent left-to-right intrapulmonary shunting postoperatively. Their ligation and control require precise preoperative definition of their number, origin, and course, and special intraoperative methods for their exposure. Associated hypoplasia of the pulmonary arteries may be severe enough to preclude corrective operation, but these hypoplastic arteries may enlarge in response to increase of blood flow through them resulting from a surgically created shunt. Experience with 14 surgically managed cases of this type forms the basis for the report.