Fractional Flow Reserve: The Ideal Parameter for Evaluation of Coronary, Myocardial, and Collateral Blood Flow by Pressure Measurements at PTCA

To overcome the fundamental limitations of coronary arteriography to assess the functional significance of coronary artery disease, it is necessary to obtain direct information about coronary blood flow. Recently we validated three pressure flow equations, which enable calculation of maximum coronary, myocardial, and collateral flow by merely measuring aortic, central venous, and distal coronary pressures under the condition of maximum vasodilation and using an ultra thin pressure monitoring guide wire for distal coronary pressure recording. In this paper, the first clinical experiences of this method are described. For that purpose, the concept of fractional flow reserve (FFR) is important. Fractional coronary flow reserve (FFR_cor) is defined as the maximum achievable blood flow in a stenotic artery, divided by normal maximum flow in that same artery, i.e. maximum flow in that artery in the case that it would be completely normal. Fractional myocardial flow reserve (FFR_myo) is defined in a similar way, and recruitable collateral blood flow is expressed as a fraction of normal maximum myocardial flow. Fractional flow reserve, defined in this way, is easy to obtain at percutaneous transluminal coronary angioplasty (PTCA) by the pressure-flow equations, is independent of pressure changes, applicable to three vessel disease, and enables calculation of the separate contribution of coronary and collateral flow to total myocardial perfusion. In 18 patients a very close correlation was demonstrated between FFR_myo, calculated by pressure recordings at PTCA by the first pressure flow equation, and FFR_myo obtained by positron emission tomography, which is considered the gold standard for myocardial perfusion. In 60 other patients, maximum recruitable collateral blood flow at balloon inflation (Q_c/Q^N) was calculated according to the third pressure-flow equation and correlated to the presence or absence of ischemia. It could be demonstrated that Q_C/Q^N exceeds 22% in all 23 patients without ischemia, whereas Q_c/Q^N was less than 22% in 34 out of 37 patients who experienced ischemia during balloon inflation. This margin value of 22% is very close to the theoretically expected value of 20%. based upon a coronary flow reserve of 5 under standard physiologic conditions. It can be concluded that the concept of fractional flow reserve provides a rapid, accurate, and elegant way for quantitative assessment of maximum coronary and myocardial blood flow before and after PTCA. Moreover, this is the first method that enables quantitative calculation of collateral blood flow in clinical practice. (J Interven Cardiol 1993; 6:331–344)     

Episodic erythema gyratum repens with ichthyosis and palmoplantar hyperkeratosis without signs of internal malignancy

Two patients with typical lesions of erythema gyratum repens, peripheral ichthyosis, palmoplantar hyperkeratosis and nail changes are described. A non-specific erythrodermic eruption of several weeks' duration had preceded the typical lesions. No signs of internal malignancy were found and the typical gyrate lesions disappeared within some weeks with full restitution of all skin lesions within 6-8 months.     

Cryosurgery in cutaneous leishmaniasis

Thirty patients with cutaneous leishmaniasis were treated with cryotherapy using a CO₂ cryomachine and all were cured without noticeable scarring within 4–5 weeks, with no relapse. Histopathological examination showed that cryotherapy eradicated all parasites in less than 1 hour. Leishmania tropica, L. ethiopica and L. brasiliensis are all markedly thermosensitive and thus cryotherapy seems parasiticidal to all types. Adequate cryotreatment of cutaneous leishmaniasis will preclude the development of mucocutaneous extension, and its use in mucocutaneous disease is also recommended.     

Proximal plaque accumulation with two minor connector designs

The relationship of plaque accumulation to two different designs of a proximal minor connector, was studied in twenty-seven removable partial denture wearers. On thirty proximal surfaces adjacent to a closed space design, and on thirty-two surfaces adjacent to an open space design, plaque formation was recorded using a plaque scoring system. Mean plaque scores were calculated separately for the two types of design, and no difference was found between the two sets of scores.     

Control of cerebrospinal meningitis epidemics with sulfadimidine and penicillin; report on an experiment in mass chemoprophylaxis in the Sudan

Four villages in Kordofan Province of the Sudan were selected by the authors to determine the effectiveness of mass prophylactic treatment with sulfa drugs and penicillin in controlling cerebrospinal meningitis epidemics in rural areas with highly primitive living conditions. Sulfadimidine was given orally in two of the villages, and procaine penicillin G in oil with 2% aluminium monostearate (PAM) was given intramuscularly in the other two. The population of the villages was classified by age and by sex and given the following prophylactic doses: in Kaldung village, where 93% of the population was treated, 4 g of sulfadimidine were given to persons over 15 years of age, 2.5 g to those between 15 and 5, and 1.5 g to those under 5; in Korongo Abdulla, the same age-groups received 2.0 g, 1.0 g, and 0.5 g, respectively, and 34% of the population was treated; in El Machicha and Miri Bara villages, PAM was given to 38% and 90% of the respective populations in the dosage of 150,000 units to those over 15 years of age, 100,000 units to those between 15 and 5, and 75,000 to those under 5.     

Qualitative changes in dental plaque formation related to removable partial dentures

A study was performed on the microbial composition of dental plaque developing on fifteen abutment teeth in nine partially edentulous subjects. Bacteria were counted in samples of plaque which had formed on vestibular surfaces, and on proximal surfaces facing edentulous spaces, during a period when dentures were not worn, and then for a period when dentures were being worn. It was found that the presence of removable partial dentures favoured a proliferation of spiral organisms.     

Standardizing the assessment of diarrhea in clinical trials: results of an interobserver agreement study

Interobserver agreement was determined between nurses and parents using a standard method of assessing diarrheal stools. The study population consisted of patients less than three years of age hospitalized at The Hospital for Sick Children, Toronto, Canada. Stool samples were independently categorized by observer pairs within minutes of being obtained from children with and without diarrhea as: watery—liquid, no solid elements; loose—liquid with solid elements; pasty—like a paste; formed—normal solid. Watery and loose stools were regarded as abnormal and indicative of diarrhea. Teaching sessions were conducted for nursing shifts, while parents were instructed prior to each observation. In the nurses' agreement study, each stool specimen was examined by the nurse providing care to the patient from whom the stool was obtained and a nurse not looking after the patient. Parents' assessments were also compared with nurses' assessments. Finally, parents' assessments were compared with each other. In the first group, agreement beyond chance for presence or absence of diarrhea measured by kappa was 0.78 (95% confidence intervals (CI) 0.55–1.0). The observed agreement on 148 pairs of observations between parents and nurses was 75% (kappa = 0.5; 95% CI 0.36–0.64). Between-parent agreement on 30 other paired observations was 77% (kappa = 0.54; 95% CI 0.24–0.84). Teaching parents about the four categories is a potentially useful adjunct for assessment of diarrheal stools in children.