Search PubMed⌕ Search

Biomedical subjects

C K Mok

Publications and source records attributed to C K Mok.

At least 55 records · Page 3Linked to original sources
PubMed1986

Atrioventricular septal defect after surgical resection of a subaortic shelf.

Left ventricular to right atrial (LV-RA) communications are rare septal defects. The majority of them are congenital in origin and acquired defects are exceedingly rare. The causes of acquired LV-RA communications include chest trauma, infective endocarditis, and valvar replacement. This report describes a case of direct LV-RA and interventricular communications occurring three months after excision of a subaortic shelf.

Aorta↗
PubMed1986

Radiological diagnosis of leiomyosarcoma of the inferior vena cava.

A 46-year-old lady with leiomyosarcoma of the inferior vena cava extending into the hepatic veins and right atrium is described. The diagnosis was made preoperatively by a combination of radiological techniques including computed tomography, inferior vena cavography, arteriography, and two-dimensional echocardiography. The clinical presentation, radiological features and management of this condition are reviewed.

Female↗
PubMed1986

An echocardiographic study of perimembranous ventricular septal defect with left ventricular to right atrial shunting.

Twenty nine patients with isolated perimembranous ventricular septal defects were investigated by M mode, cross sectional, and pulsed Doppler echocardiography. Tricuspid valve anomalies were present in all six patients with a left ventricular-right atrial shunt but in only six (26%) of 23 patients who had interventricular shunts only. Systolic flutter of the tricuspid valve was shown in five (83%) of the six patients with a ventriculoatrial shunt but not in the other patients. Systolic turbulence in both the right ventricle and right atrium was detected by Doppler echocardiography only in patients with ventriculoatrial shunting. A perimembranous ventricular septal defect with left ventricular to right atrial shunt can be diagnosed by its combined M mode, cross sectional, and pulsed Doppler echocardiographic features.

Adolescent↗
PubMed1986

The role of cross sectional echocardiography and pulsed Doppler ultrasound in the management of neonates in whom congenital heart disease is suspected. A prospective study.

The application of cross sectional echocardiography and pulsed Doppler ultrasound to the management of symptomatic neonates with suspected congenital heart disease was studied in 96 consecutive cases. The ability of echocardiography to establish a complete and accurate diagnosis and a correct management plan was evaluated. Sequential segmental analysis of data from cardiac catheterisation and necropsy identified 536 cardiovascular anomalies. Of the 536 anomalies 512 were correctly diagnosed by echocardiography (sensitivity 95.5%). Seven false positive echocardiographic diagnoses were made (specificity 98.6%). Nearly all the missing diagnoses and all the false positive diagnoses made by echocardiography were extracardiac vascular anomalies. Normal cardiovascular anatomy was at all times correctly identified by echocardiography. In 12 babies (12.5%) a management plan could not be established because of inconclusive echocardiographic findings. Of the 84 proposed plans based on the echocardiographic findings, eight were found to be inappropriate after catheterisation. Thus, 76 babies (79.2%) could have been correctly managed without cardiac catheterisation. The combination of cross sectional echocardiography and pulsed Doppler ultrasound not only allows diagnosis of congenital cardiac anomalies in most neonates but can facilitate appropriate clinical management. Only a minority of neonates with suspected congenital heart disease require cardiac catheterisation and angiography.

Aortography↗
PubMed1986

Thymectomy in myasthenia gravis during pregnancy.

A 24 year old woman with myasthenia gravis suffered an antepartum exacerbation which failed to respond to increasing dosages of pyridostigmine. Thymectomy performed in the second trimester was followed by clinical improvement and full term vaginal delivery with no puerperal deterioration.

Adult↗
PubMed1986

Endobronchial tuberculosis revisited.

Analysis was made of 20 patients with endobronchial tuberculosis proven by fiberoptic bronchoscopy and bronchial biopsy. Unlike prechemotherapy reports, the disease affects the older age group and more men. Only one half of the patients had fever, and the characteristic localized wheeze was found in 15 percent of cases. Chest roentgenogram showed typical collapse-consolidation in most cases; however, it was clear in 20 percent of patients. Sputum/smear was negative for AFB in 85 percent of patients. When the gelatinous granulation tissue was not found during bronchoscopy, a diagnosis of bronchogenic carcinoma was made incorrectly in 30 percent of patients. At a mean period of 27 months postchemotherapy, all 12 patients recalled for study developed bronchostenosis proven by bronchoscopy/bronchography except one. Noninvasive methods such as chest roentgenogram and flow-volume loops were insensitive for detection of stenosis. Steroid therapy probably did not influence outcome of tuberculous endobronchitis.

Adolescent↗
PubMed1985

Experience with outlet strut fracture of the Björk-Shiley convexoconcave mitral valve prosthesis.

Within a period of 15 months, we encountered five patients with outlet strut fracture of the Björk-Shiley convexoconcave mitral valve prosthesis. All of the patients had acute failure of the left side of the heart and pulmonary edema. The diagnosis was made by review of the chest roentgenogram which showed features of pulmonary edema; both the outlet strut and the tilting disc were missing from the mitral prosthesis. The "missing" components might be found in the left side of the heart or in the course of the thoracic aorta. Emergency reoperation was carried out on three patients, and there were two survivors. It is essential to recognize this potentially fatal complication and undertake immediate surgical intervention. We performed the original valvular replacement operations in four of the five patients. The probability of outlet strut fracture occurring in our series of 237 patients with a Björk-Shiley convexoconcave mitral valve prosthesis is 1.69%, or 0.076 per 100 patient months.

Adolescent↗
PubMed1985

Pulmonary scar cancer. A pathologic reappraisal.

A total of 49 consecutive specimens of lung cancer were collected prospectively at surgical resection or autopsy from 40 men and nine women, aged 40-74 years. Of the 49 tumors, the gross appearance of 22 fitted the description of a scar cancer, i.e., a tumor with pleural puckering and central pigmentation. Nineteen of the "scar cancers" were peripheral (17 adenocarcinomas and two squamous cell carcinomas); three were central (one squamous cell carcinoma and two adenocarcinomas). In the 19 peripheral "scar cancers," elastic stains demonstrated the presence of collapsed, unfibrosed lung tissue at the center with traction of the overlying pleura toward it. Elsewhere in the tumor, the elastic framework was either destroyed or expanded by tumor filling the alveolar spaces. None of the "scar cancers" had a significant desmoplastic reaction that might otherwise explain the scarred appearance. It appeared that local atelectasis was solely responsible for the pleural puckering and central pigmentation. On the other hand, atelectatic lung tissue was not seen in the 27 cancers that did not have the appearance of a scar cancer. Tuberculosis was found in 10 of the 49 lung specimens. In only one specimen was the tuberculous lesion anatomically associated with the tumor. There was no evidence of pulmonary infarct in any of the specimens. The term "scar cancer" was considered inappropriate as there was no preformed fibrous tissue. The scarred appearance was thought to be the result of localized pulmonary atelectasis owing to small airways obstruction by tumor. Association with tuberculosis was considered incidental.

Adenocarcinoma↗
PubMed1985

Unruptured right coronary sinus to left ventricle aneurysm diagnosed by cross sectional echocardiography.

A 37 year old Chinese man presenting with features of chest infection was diagnosed as having severe aortic regurgitation. Cross sectional echocardiography showed an intact right coronary sinus of Valsalva aneurysm, which protruded into the left ventricle. The changes in appearance of the aneurysm during the cardiac cycle were recorded by cross sectional echocardiography. The opening of the aneurysm was successfully closed and the aortic valve replaced with a mechanical prosthesis.

Adult↗
PubMed1985

Warfarin versus dipyridamole-aspirin and pentoxifylline-aspirin for the prevention of prosthetic heart valve thromboembolism: a prospective randomized clinical trial.

In a prospective, randomized, parallel study, two regimens of platelet-suppressant therapy (PST)--dipyridamole-aspirin and pentoxifylline-aspirin--were compared with standard oral anticoagulation with warfarin in the prevention of prosthetic heart valve thromboembolism. In the entire group of 254 patients followed for 395.6 patient-years, the thromboembolic rate was significantly less in the warfarin group (warfarin vs dipyridamole-aspirin, p less than .005; warfarin vs pentoxifylline-aspirin, p less than .05). Subgroup analysis disclosed that, in patients with isolated mitral valve replacement, warfarin was superior to both of the PSTs with respect to the prevention of thromboembolism (warfarin vs dipyridamole-aspirin, p = .005; warfarin vs pentoxifylline-aspirin, p less than .05). Furthermore, a significant number of our patients could not tolerate the antiplatelet agents. However, in the rare situation in which repeated significant bleeding occurs despite careful adjustment of the dosage of warfarin, PST may be an acceptable alternate method of thromboembolism prophylaxis.

Adult↗
PubMed1983

First report of asbestos-related diseases in Hong Kong.

There has been no report of malignant mesothelioma or asbestosis in Hong Kong despite the rapid growth of industry in the past few decades. Three patients with malignant pleural mesothelioma and one patient with asbestosis and small cell carcinoma of the lung are reported. All four patients were Chinese in Hong Kong and had a history of occupational exposure to asbestos. Although there is no mining of asbestos in Hong Kong, her rapid industrialization in the past few decades has led to a large population of asbestos-exposed workers in industry. The average annual consumption of crude asbestos (import minus re-export) has grown ten-fold in the past decade to 1.090 tonnes in 1978-79, and the number of workers handling asbestos products was estimated to be 20.000 in 1979. The problem of asbestos related diseases has however been little considered and further epidemiologic studies are warranted.

Adult↗
PubMed1982

Is cardiac catheterisation necessary before valvular surgery?

The results of 269 patients who had undergone valvular operations during and 18-month period (January 1, 1980, to June 30, 1981) were analysed. One hundred and seventy-four patients referred for surgery had undergone routine cardiac catheterisation elsewhere, and these, together with four electively catheterised patients, constituted a group representing the conventional approach. Ninety-one patients were assessed only by clinical and non-invasive methods, including echocardiography, and were subjected to surgery without catheterisation. The two groups were comparable in their major clinical characteristics including age, sex ratio, functional class, previous history of closed mitral valvotomy, aetiology of valve lesions, and type of operative procedure performed. There was no discordance between operative finding and preoperative assessment, except in two patients of the catheterised group. Hospital mortality was acceptably low and was comparable between the two groups. Cardiac catheterisation is, thus, no longer necessary in the majority of patients undergoing surgery for valvular heart diseases.

Adult↗
PubMed1982

Coronary artery to left ventricle fistulas: echocardiographic features.

The echocardiographic features of a coronary artery fistula that drains into the left ventricle were described in two patients. The clinical picture mimicked moderate to severe aortic insufficiency; however, M-mode echocardiogram revealed unusual features. Diastolic fluttering of the anterior mitral leaflet and the septum was absent in the first patient, while the second patient had marked diastolic fluttering of the posterior mitral leaflet and the left ventricular wall at the atrioventricular junction. In both, the coronary artery fistula could be visualized by cross-sectional echocardiography. Contrast echocardiography performed during cardiac catheterization in the second patient demonstrated that the diastolic fluttering of the posterior mitral leaflet was related to the jetting of blood from the coronary artery fistula.

Adult↗