Septal perforator arteries: from angiographic-morphologic characteristics to related revascularization options

Linear late gadolinium enhancement in the basal anterior septum and lateral wall may represent the contrast enhancement of vessels: A CMR and CCTA comparison study

BACKGROUND

The purpose of this paper was to verify that the linear high-intensity signal on late gadolinium enhancement-cardiac magnetic resonance (LGE-CMR) may represent the contrast enhancement of vessels rather than scars or fibrosis, and to assess whether this linear high-intensity signal will affect the quantification of myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM).

METHODS

A total of 58 patients who underwent both coronary computed tomography angiography (CCTA) and LGE-CMR in our hospital were ultimately enrolled. The definitions of positive linear LGE (LLGE+) were as follows: (1) LLGE in the basal anterior septum or lateral wall, and (2) LLGE observable at 10 mm or more. All other patients were regarded as negative LLGE (LLGE-). In LLGE+ patients, the length of the LLGE located in the anterior septum and lateral wall was compared with the length of the septal perforator artery and the circumflex artery on CCTA, respectively. For nine patients with HCM, the LGE% was measured before and after removal of LLGE.

RESULTS

Among the 58 patients, 40 showed LLGE+ and 18 showed LLGE-. For patients with LLGE in the anterior septum, there was a strong correlation between LLGE and anterior septal perforator arteries in length (r=0.887, p<0.001). For patients with LLGE in the lateral wall, LLGE also correlated well with the circumflex arteries in length (r=0.962, p<0.001). In nine patients with HCM, the LGE% decreased significantly after the removal of LLGE [9.50 (7.70 - 17.35)% vs. 8.80 (6.20 - 15.55)%, p<0.05].

CONCLUSIONS

The LLGE in the anterior septum and lateral wall may represent contrast enhancement of the anterior septal perforator artery and the circumflex artery, respectively. This LLGE may overestimate the extent of myocardial fibrosis in patients with HCM.

What is the mid-wall linear high intensity "lesion" on cardiovascular magnetic resonance late gadolinium enhancement?

BACKGROUND

Cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) is a valuable technique for detecting myocardial disorders and fibrosis. However, we sometimes observe a linear, mid-wall high intensity signal in the basal septum in the short axis view, which often presents diagnostic difficulties in the clinical setting. The purpose of this study was to compare the linear, mid-wall high intensity in the basal septum identified by LGE with the anterior septal perforator arteries identified by coronary computed tomography angiography (CorCTA).

METHODS

We retrospectively selected 148 patients who underwent both CorCTA and CMR LGE within 1 year. In the interpretation of LGE, we defined a positive linear high intensity (LHI+) as follows: ① LHI in the basal septum and ② observable for 1.5 cm or more. All other patients were defined as a negative LHI (LHI-). In LHI+ patients, we assessed the correlation between the LHI length and the septal perforator artery length on CorCTA. We also compared the length of the septal perforator artery on CorCTA between LHI+ patients and LHI- patients.

RESULTS

A population of 111 patients were used for further analysis. Among these , there were 55 LHI+ patients and 56 LHI- patients. In LHI+ patients, linear regression analysis revealed that there was a good agreement between LGE LHI and septal perforator arteries by CorCTA in terms of length measurements. The measured length of the anterior septal perforator arteries was significantly shorter in LHI- patients than in LHI+ patients (10 ± 8 mm vs. 21 ± 8 mm; P < 0.05).

CONCLUSIONS

The LHI observed in the basal septum on short axis LGE may reflect contrast enhancement of the anterior septal perforator arteries. It is important to interpret this septal LHI against knowledge of anatomic structure, to avoid misinterpretations of LGE and prevent misdiagnosis.

Double Posterior Descending Artery Arising from a Right Coronary Artery

This paper presents two cases of human hearts (a 75-year-old woman and an 88-year-old man) with double posterior descending arteries (PDA) of various sizes originating from the right coronary artery, mainly supplying the interventricular septum as well as the posterior walls of both heart ventricles in a different scope. In the analysis of the arterial vasculature, a range of aspects were considered, such as the point of exit of the right coronary artery, the course of the vessel, the range of the blood supply of the interventricular septum and both ventricles, as well as selected morphometric parameters that were simultaneously compared with one another. These atypical changes presented based on the example of the analyzed cases will certainly constitute a valuable source of information for cardiac surgeons and interventional cardiologists in planning operations.

Individual variability of vascularization of the anterior papillary muscle within the right ventricle of human heart

Background

To date there is scarce published evidence reporting the dual blood supply reaching anterior papillary muscle (APM), which descends from both major coronary arteries. Such a vascular configuration can prevent the dysfunction of right ventricular entire valvular system in case of the occlusion of proximal part of either right coronary artery (RCA) or left coronary artery (LCA). The aim of our study was to determine the vascular pattern of APM blood supply which originates from two main coronary arteries, in the context of the APM and septomarginal trabecula (SMT) topography.

Methods

The study was carried out using tissue obtained from 36 human hearts. The material was divided into four morphological types of SMT/APM arrangement. Vascularization and blood supply pattern of papillary muscle was investigated following the analysis of multiple tissue cross sections. The origin of APM arterial supply was traced back to both main coronary arteries. Cross-sectional area of the arteries was estimated at the base of APM and compared within mixed male-female population, aged 18–76.

Results

We noted that as much as 78% of entire APM material had a blood supply vasculature originating from both LCA and RCA branches. In contrast, 22% of cases APM was supplied by a single coronary artery, while in each case it proved to be LCA. We have never found APM arterial supply provided exclusively by RCA. In case of double AMP blood supply an average of total cross-section area of the arteries branching from LCA, was noted to be in excess of two and a half times bigger in type III and more than two times bigger in type IV, as compared with the arteries originating from RCA.

Conclusions

Our research confirm the possibility of double blood supply which vascularizes APM, but the finding does not necessarily apply in all cases. However, APM seems to be predominantly vascularized by arteries deriving from LCA, regardless of their morphological type.

The role of septal perforators and "myocardial bridging effect" in atherosclerotic plaque distribution in the coronary artery disease

The distribution of atherosclerotic plaque burden in the human coronary arteries is not uniform. Plaques are located mostly in the left anterior descending artery (LAD), then in the right coronary artery (RCA), circumflex branch (LCx) and the left main coronary artery (LM) in a decreasing order of frequency. In the LAD and LCx, plaques tend to cluster within the proximal segment, while in the RCA their distribution is more uniform. Several factors have been involved in this phenomenon, particularly flow patterns in the left and right coronary artery. Nevertheless, it does not explain the difference in lesion frequency between the LAD and the LCx as these are both parts of the left coronary artery. Branching points are considered to be the risk points of atherosclerosis. In the LCx, the number of side branches is lower than in the LAD or RCA and there are no septal perforators with intramuscular courses like in the proximal third of the LAD and the posterior descending artery (PDA). We hypothesized that septal branches generate disturbed flow in the LAD and PDA in a similar fashion to the myocardial bridge (myocardial bridging effect). This coronary architecture determines the non-uniform plaque distribution in coronary arteries and LAD predisposition to plaque formation.

Right superior septal artery with "normal" right coronary and ectopic "early" aortic origin: a contribution to the vascular supply of the interventricular septum of the human heart

In the human heart, anterior and posterior septal branches are mainly responsible for the arterial supply of the interventricular septum. These arteries are the basis of efficient intercoronary collateralization. The right and left superior septal arteries also contribute to the nourishment of the septum and to any eventual collateralization. Because the right superior septal artery (RSSA) is small in diameter, short, and has a variable origin either at the proximal stem or in the ostial area of the right coronary artery, it is difficult or almost impossible to visualize it angiographically. During investigation of the arterial supply of the interventricular septum in 84 human heart specimens and 16 corrosion casts, we found a few peculiarities in the origin and pattern of the RSSA in four specimens. The RSSA was found in 27 cases (27%); in most it was a single vessel and arose from three different locations: (a) the proximal part of the right coronary artery (21 cases); (b) the right coronary ostial area (four cases); and (c) from the floor of the right (anterior) aortic sinus (two cases). Macroscopically, in 16 cases the RSSA had a length of less than 10 mm; in nine cases the arteries were between 11 and 17 mm long. In two cases the RSSA was of more substantial appearance and up to 36 mm in length; it nourished almost the entire upper third of the septal myocardium. In these two cases, two courses could be differentiated: an extramural course with the RSSA descending to the subvalvular fibrous tissue, and an intramural course with ramification in the myocardium of the crista supraventricularis and the superior parts of the interventricular septum. One cadaveric heart specimen and one corrosion cast showed RSSAs that originated "early" (ectopically) on the floor of the right (anterior) aortic sinus; their total lengths were 16 and 17 mm, respectively. Such ectopic ostia of RSSAs have never been described before in the anatomical literature. Given the intense clinical concern with the identification of possible bypass vessels in the myocardium, we assume that the RSSA may have a potential as a collateral route. These findings were also discussed in light of developmental and comparative anatomy.

Arterial vascularization of the human moderator band: an analysis of this structure's role as a collateral circulation route

In the human heart, the moderator band, or trabecula septomarginalis, is a muscle column that courses inferiorly from the right portion of the interventricular septum to the base of the anterior papillary muscle of the right ventricle This muscular structure is crossed by one or more arteries, which come from the anterior interventricular artery and perfuses the anterior papillary muscle of the right ventricle. In order to clarify the arterial supply of this muscle column, we studied 28 adult hearts, free of any signs of coronary disorder. The path of the moderator band artery was followed by means of microdissection, and we studied the source, course, and interconnections made with other arteries. We observed that the source of the moderator band artery lies in the first three anterior septal arteries, most often in the second one. In relation to the short axis of the heart, the artery of the moderator band can either follow a horizontal path to the septal papillary muscle of the right ventricle or an oblique route to the moderator band, depending on the position of its source. In all the hearts studied, the moderator band artery made anastomotic connections at the base of the anterior papillary muscle of the right ventricle with various branches of the right coronary artery, which means that it can play a key role in collateral circulation following obstruction of the epicardium coronary arteries.

Dual anterior interventricular arteries

A patient with dual left anterior descending (R. interventricularis anterior of the left coronary artery) coronary artery is presented. A normally arising left anterior descending was hypoplastic, and an anomalous left anterior descending, which arose from the right sinus aorticus had a normal caliber. The anomalous left anterior descending artery traversed between the aorta and the pulmonary artery supplying most of the anterior myocardial wall of the left ventricle. This rare coronary anomaly can potentially have implications on percutaneous coronary interventions or on surgical revascularization procedures.

Symptomatic hypertrophic obstructive cardiomyopathy: the role of dual-chamber pacing

BACKGROUND AND PURPOSE

The management of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) has traditionally consisted of beta blockers and calcium channel blockers. Surgical treatment has been employed for operable patients who became refractory to medical therapy. However, associated complications, mortality rate, and recurrence of functional limitations have shifted the focus toward alternative therapy modalities. Recently, permanent dual-chamber (DDD) pacemaker has been introduced as an alternative treatment option.

PATIENTS AND METHODS

This study comprises clinical, angiographic, echocardiographic, and electrophysiologic data obtained at a single center on 10 symptomatic patients with HOCM who received a DDD pacemaker after medical therapy failed to relieve symptoms. Presenting symptoms were exertional dyspnea and chest pain (60%), syncope (20%), and presyncope (20%). These symptoms were documented for 8.9+/-7.1 years before pacemaker implantation. All patients were in New York Heart Association functional class III or IV before pacemaker therapy.

RESULTS

Placement of a permanent DDD pacemaker decreased the left ventricular outflow tract gradient from 83+/-44 mm Hg (range: 35-180 mm Hg) to 47.1+/-25.3 mm Hg (range: 10-75 mm Hg) in these patients. Within 1 to 30 months, follow-up found that the functional status of eight out of the 10 patients had improved to New York Heart Association class 0 or I.

CONCLUSION

In selected patients with symptomatic HOCM who fail to respond to medical therapy, DDD pacemaker may offer a nonsurgical alternative treatment option. Large-scale multicenter, prospective, randomized trials are needed to establish the role of this modality in the treatment of hypertrophic obstructive cardiomyopathy.

Anomalous first septal perforator artery: anatomic-clinical correlates

The interventricular septum is considered the most densely vascularized portion of the heart, containing important elements of the cardiac conduction system and providing mechanical support for both right and left ventricular function. Anatomically, this structure is perfused by the relatively small caliber anterior and posterior septal perforator branches arising from two large epicardial coronary vessels, the anterior interventricular (descending) branch of the left coronary artery and the posterior interventricular (descending) branch of the right coronary artery, respectively. In cases of significant atherosclerotic disease depriving flow in the major coronary vessels and their septal branches, an anomalous septal perforator artery can take over the task of supporting the function of the interventricular septum by supplementing essential collateral flow.