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Diagnostic angiography Left‐sided views
ОглавлениеThe first view is chosen to identify LMS disease. Either a posteroanterior (PA) view with minimal angulation to the right to project the catheter tip off the spine or a caudal left anterior oblique (LAO, (the so‐called spider) view, are used most often. At least three to four perpendicular views are required to visualize the left coronary tree (Table 4.1 shows the most widely used combinations of views). In many patients these views would suffice, potentially even when proceeding immediately to angioplasty. However, because of variations in patient anatomy, such as increased overlap caused by prominent tortuosity, displacement, or rotation of the heart axis in the chest (e.g. when there is normal anatomic variation, chest wall deformity, previous cardiothoracic surgery, or lung pathology), modification of views or additional views are sometimes required. When a lesion is identified, additional views can be indicated depending on how well the affected coronary segment has been straightened and visualized (Table 4.2).
Table 4.1 Angiographic projections and optimal visualization of left and right coronary artery segments.
| Coronary artery segment | LAO 40–50° Caudal 25–40° (spider) | AP RAO 5–15° Caudal 30° | RAO 30–45° Caudal 30–40° | AP/RAO 5–10° Cranial 35–45° | LAO 35–40° Cranial 25–35° | Lateral ± Caudocrania10–30° | l LAO 45–60° | RAO 30–45° |
|---|---|---|---|---|---|---|---|---|
| LM ostium | ++ | + | + | +++ | +++ | – | – | – |
| LM bifurc | +++ | +++ | ++ | – | – | – | – | – |
| LAD prox | ++ | ++ | +++ | ++ | ++ | + | – | – |
| LAD mid | – | + | + | +++ | ++ | ++ | – | – |
| LAD dist | + | + | +++ | + | – | +++ | – | ++ |
| LAD/DG | ++ | + | – | ++ | +++ | – | – | – |
| LCX prox | + | +++ | +++ | – | – | – | – | – |
| LCX dist | + | + | ++ | +++ | ++ | + | ++ | – |
| OM bifurc | ++ | +++ | ++ | – | – | – | + | – |
| RCA prox | – | – | – | + | +++ | – | ++ | – |
| RCA mid | – | – | – | – | + | +++ | ++ | +++ |
| RCA dist/crux | – | – | – | +++ | +++ | – | ++ | – |
| PDA | – | – | – | +++ | ++ | – | + | ++ |
| PLV | + | – | – | +++ | ++ | + | + | – |
| LIMA anast | + | – | – | – | – | +++ | – | – |
– not recommended; + occasionally useful; ++ very useful; +++ ideal.
AP, anteroposterior; LAD, left anterior descending; LAO, left anterior oblique; LCX, left circumflex; LIMA, left internal mammary artery; OM, obtuse marginal; PDA, posterior descending artery; PLV, posterior left ventricular; RAO, right anterior oblique; RCA, right coronary artery.
Table 4.2 Popular view combinations for diagnostic angiography with benefits and limitations of each view.
| View | Good for visualizing | Limitations |
|---|---|---|
| Combination 1 | ||
| AP (5–10° RAO) | LMS (ostium and main shaft) | Overlap on LMS bifurcation and sometimes LMS ostium with left coronary sinus |
| Lateral | Mid and distal LAD, mid Cx | Potentially high radiation dose to operator, usually limited view of proximal LAD, patient’s arms need to be above head to visualize posterior arteries, often overlap diagonals/LAD |
| RAO cranial | Proximal and mid LAD, distal Cx | Test injections can be required to adjust angulation to ensure diagonals are above LAD, overlap with dominant Cx, and position of the diaphragm |
| RAO caudal | Circumflex and distal LAD | |
| Combination 2 | ||
| LAO caudal | LMS bifurcation, proximal LAD and proximal circumflex | Potentially a higher radiation dose to the patient, poor quality images sometimes in large patients |
| LAO cranial | Mid LAD, origin of diagonals, proximal and mid Cx | Patient required to hold in inspiration during acquisition to elongate the proximal LAD |
| AP cranial | Proximal and mid LAD, distal Cx | Steep cranial angulation required can be a problem for patients with cervical spine fixation |
| RAO caudal | Circumflex and distal LAD, sometimes LAD ostium |
AP, anteroposterior; Cx, circumflex; LAD, left anterior descending; LAO, left anterior oblique; LMS, left main stem; RAO, right anterior oblique.
