Retention behavior of conjugated and isolated n-alkadienes. Identification of n-nona- and n-decadienes by capillary gas chromatography using structure-retention correlations and mass spectrometry

The isomerization products of n-C8---C10 a,¿-alkadienes were separated on a high-efficiency squalane column (195 m × 0.25 mm I.D.) with 500,000 effective plates. Of the 102 possible n-C8---C10 dienes with isolated and conjugated double bonds, only nine groups of isomers were not separated. All isomers, except those with cumulated double bonds, were identified (23 octadienes, 33 nonadienes and 46 decadienes). The n-octadienes were identified by matching measured and published retention data. Because of the lack of standards, retention data and mass spectra of n-nona- and decadienes, and because the previously reported identification method for n-dienes up to C8 was succesful, the problem of the identification of C9---C10 n-alkadienes was solved similarly by using structure-retention correlations and combined capillary gas chromatography-mass spectrometry. Based on these results, the retention behaviour of the conjugated and isolated n-alkadienes, on squalane stationary phase, is generalized

Surgery for anomalous aortic origin of coronary arteries : a multicentre study from the European Congenital Heart Surgeons Association

OBJECTIVES: We sought to describe early and late outcomes in a large surgical series of patients with anomalous aortic origin of coronary arteries. METHODS: We performed a retrospective multicentre study including surgical patients with anomalous aortic origin of coronary arteries since 1991. Patients with isolated high coronary takeoff and associated major congenital heart disease were excluded. RESULTS: We collected 156 surgical patients (median age 39.5 years, interquartile range 15-53) affected by anomalous right (67.9%), anomalous left (22.4%) and other anatomical abnormalities (9.6%). An interarterial course occurred in 86.5%, an intramural course in 62.8% and symptoms in 85.9%. The operations included coronary unroofing (56.4%), reimplantation (19.2%), coronary bypass graft (15.4%) and other (9.0%). Two patients with preoperative cardiac failure died postoperatively (1.3%). All survivors were discharged home in good clinical condition. At a median follow-up of 2 years (interquartile range 1-5, 88.5% complete), there were 3 deaths (2.2%), 9 reinterventions in 8 patients (5 interventional, 3 surgical); 91.2% are in New York Heart Association functional class <= II, but symptoms persisted in 14.2%; 48.1% of them returned to sport activity. On Kaplan-Meier analysis, event-free survival at follow-up was 74.6%. Morbidity was not significantly different among age classes, anatomical variants and types of surgical procedures. Furthermore, return to sport activity was significantly higher in younger patients who participated in sports preoperatively. CONCLUSIONS: Surgical repair of anomalous aortic origin of coronary arteries is effective and has few complications. Unroofing and coronary reimplantation are safe and are the most common procedures. The occurrence of late adverse events is not negligible, and long-term surveillance is mandatory. Most young athletes can return to an unrestrained lifestyle

Diagnostic Yield of Non-Invasive Testing in Patients with Anomalous Aortic Origin of Coronary Arteries : A Multicentric Experience

Background: Anomalous aortic origin of a coronary artery (AAOCA) is a congenital heart disease with a 0.3%-0.5% prevalence. Diagnosis is challenging due to nonspecific clinical presentation. Risk stratification and treatment are currently based on expert consensus and single-center case series. Methods: Demographical and clinical data of AAOCA patients from 17 tertiary-care centers were analyzed. Diagnostic imaging studies (Bidimensional echocardiography, coronary computed tomography angiography [CCTA] were collected. Clinical correlations with anomalous coronary course and origin were evaluated. Results: Data from 239 patients (42% males, mean age 15 y) affected by AAOCA were collected; 154 had AAOCA involving the right coronary artery (AAORCA), 62 the left (AAOLCA), 23 other anomalies. 211 (88%) presented with an inter-arterial course. Basal electrocardiogram (ECG) was abnormal in 37 (16%). AAOCA was detected by transthoracic echocardiography and CCTA in 53% and 92% of patients, respectively. Half of the patients reported cardiac symptoms (119/239; 50%), mostly during exercise in 121/178 (68%). An ischemic response was demonstrated in 37/106 (35%) and 16/31 (52%) of patients undergoing ECG stress test and stress-rest single positron emission cardiac tomography. Compared with AAORCA, patients with AAOLCA presented more frequently with syncope (18% vs. 5%, P = 0.002), in particular when associated with inter-arterial course (22% vs. 5%, P < 0.001). Conclusion: Diagnosis of AAOCA is a clinical challenge due to nonspecific clinical presentations and low sensitivity of first-line cardiac screening exams. Syncope seems to be strictly correlated to AAOLCA with inter-arterial course.Peer reviewe

Surgery for anomalous aortic origin of coronary arteries : a multicentre study from the European Congenital Heart Surgeons Association

OBJECTIVES: We sought to describe early and late outcomes in a large surgical series of patients with anomalous aortic origin of coronary arteries. METHODS: We performed a retrospective multicentre study including surgical patients with anomalous aortic origin of coronary arteries since 1991. Patients with isolated high coronary takeoff and associated major congenital heart disease were excluded. RESULTS: We collected 156 surgical patients (median age 39.5 years, interquartile range 15-53) affected by anomalous right (67.9%), anomalous left (22.4%) and other anatomical abnormalities (9.6%). An interarterial course occurred in 86.5%, an intramural course in 62.8% and symptoms in 85.9%. The operations included coronary unroofing (56.4%), reimplantation (19.2%), coronary bypass graft (15.4%) and other (9.0%). Two patients with preoperative cardiac failure died postoperatively (1.3%). All survivors were discharged home in good clinical condition. At a median follow-up of 2 years (interquartile range 1-5, 88.5% complete), there were 3 deaths (2.2%), 9 reinterventions in 8 patients (5 interventional, 3 surgical); 91.2% are in New York Heart Association functional class CONCLUSIONS: Surgical repair of anomalous aortic origin of coronary arteries is effective and has few complications. Unroofing and coronary reimplantation are safe and are the most common procedures. The occurrence of late adverse events is not negligible, and long-term surveillance is mandatory. Most young athletes can return to an unrestrained lifestyle.Peer reviewe

Capillary gas chromatography of alkylbenzenes. I. Some problems encountered with the precision of the retention indices of alkylbenzenes

A high-precision gas chromatographic system, in combination with high-resolution stainless-steel capillary columns and three stationary phases of different polarity, was used to study the separation and retention behaviour of 47 alkyl-benzenes up to C15, including all possible isomers between C6 and C10. The precision of the relative retention data is discussed in relation to the method of time measurement, non-ideality of the carrier gas, column temperature and ageing of the column. Taking into account these factors, the inter-laboratory agreement of the retention indices for aromatic hydrocarbons determined within and between laboratories can be improved considerably. Kováts retention indices and their temperature dependence were obtained with a precision corresponding to a standard deviation of about 0.1 index unit

Capillary gas chromatography of alkylbenzenes II. Correlations between the structures and methylene group increments and differences in retention indices of isomers

The contribution to gas chromatographic retention behaviour of methylene group increments and differences in the retention indices (dI) of isomers of alkylbenzenes up to C16 on squalane and acetyltri-n-butyl citrate was studied. The methylene group increments appear to vary over a wide range (60–100 i.u.) and depend on the magnitude, positions and relative lengths of the alkyl chains and on the number of carbon atoms. Anomalous retention behaviour of n-propylbenzene and its derivatives, except for molecules in which there are alkyl groups in both positions vicinal to the n-propyl group, was found. Hence, the correlations of ICH2 in homologous series can serve as indicators of fine structural peculiarities of the molecules. The applicability of regularities in methylene group increments and dI values, based on precise measurements of retention indices of low-molecular-weight alkylbenzenes, for confirmation of the identities of high-molecular-weight alkylbenzenes ( > C10) is demonstrated

Correlations between boiling points and relative retention data for hydrocarbons

An equation correlating retention indices, boiling points and activity coefficients is proposed. The equation can be applied not only to homologous series, but also to different classes of hydrocarbons

Retention behavior of conjugated and isolated n-alkadienes. Identification of n-nona- and n-decadienes by capillary gas chromatography using structure-retention correlations and mass spectrometry

The isomerization products of n-C8---C10 a,¿-alkadienes were separated on a high-efficiency squalane column (195 m × 0.25 mm I.D.) with 500,000 effective plates. Of the 102 possible n-C8---C10 dienes with isolated and conjugated double bonds, only nine groups of isomers were not separated. All isomers, except those with cumulated double bonds, were identified (23 octadienes, 33 nonadienes and 46 decadienes). The n-octadienes were identified by matching measured and published retention data. Because of the lack of standards, retention data and mass spectra of n-nona- and decadienes, and because the previously reported identification method for n-dienes up to C8 was succesful, the problem of the identification of C9---C10 n-alkadienes was solved similarly by using structure-retention correlations and combined capillary gas chromatography-mass spectrometry. Based on these results, the retention behaviour of the conjugated and isolated n-alkadienes, on squalane stationary phase, is generalized