Type A aortic dissection with left coronary malperfusion.

Left coronary artery malperfusion is a fatal complication of acute type A aortic dissection. However, effective treatment strategies have not yet been established. Herein, we report two cases of left coronary artery malperfusion successfully treated with different preoperative catheter interventions, followed by a central aortic repair. Preoperative coronary intervention ensuring the blood flow to the left coronary artery might be essential if a coronary angiogram was performed prior to the diagnosis and treatment.

Extra-Anatomical Bypass Grafting and Latissimus Dorsi Myocutaneous Flap Reconstruction for Post-sternotomy Mediastinitis With Prosthetic Aortic Graft Infection.

Extra-anatomical bypass grafting is a surgical method used to remove an infected aortic graft and promote revascularization with a new graft in the non-infected area. Here, we report a case of intractable post-sternotomy mediastinitis (PSM) with aortic graft infection which was treated with extra-anatomical bypass grafting. A 56-year-old woman with a history of multiple aortic dissection and prosthetic graft replacement in the thoracoabdominal area developed PSM with aortic arch graft infection. Bacterial culture of the exposed prosthetic graft tissue yielded multidrug-resistant Pseudomonas aeruginosa. Meticulous debridement of the wound and management by negative pressure wound therapy with continuous irrigation was performed. However, the infection of the prosthetic graft could not be controlled. Extra-anatomical bypass was performed between the left common carotid artery and right subclavian artery via the right common carotid artery. Then, the infected graft was removed. After the resolution of infection, the mediastinal wound was reconstructed with a pedicled latissimus dorsi myocutaneous flap, which was harvested from the right dorsum. No recurrence of infection occurred in the nine-month follow-up period. Debridement and removal of exposed artificial graft are considered the gold standard for treating wound infection. In situ replacement of infected aortic grafts carries a risk of re-infection due to residual bacterial contamination of the periprosthetic tissue. Extra-anatomical bypass would be a useful option for reducing the risk of re-infection in patients with intractable PSM and prosthetic aortic graft infection. Further studies are warranted to evaluate the risks and benefits of this operative method.

[Does Surgeons' Experience Affect the Surgical Outcomes of Total Arch Replacement?]

OBJECTIVES: Total arch replacement( TAR) is used to be a complicated and quite invasive aortic procedure. To perform TAR safely and effectively under all circumstances, we have constructed standardization of the procedures of TAR. The aim of this study is to analyze the impact of surgeons' experience on surgical outcome of TAR to evaluate our standardization. METHODS: From January 2008 to December 2020, 346 consecutive patients (mean age 73.6±10.2) underwent elective TAR through a median sternotomy at our institute. TAR was performed by three types of surgeon classified by their experience( A:over 20 years, B:15~20 years, C:under 15 years). The surgical outcomes were examined. Our standard approach include( 1) meticulous selection of arterial cannulation site and type of arterial cannula;(2) antegrade selective cerebral perfusion;(3) maintenance of minimal tympanic temperature between 20 ℃ and 23 ℃;(4) early rewarming just after distal anastomosis;(5) maintaining fluid balance below 1,000 ml during cardiopulmonary bypass. RESULTS: The operative cases were 227 in A, 86 in B and 33 in C. Surgeon A operated more complicated TAR with higher operative risk compared with B and C. The hospital mortality and major complication rate was not significant difference among surgeons( hospital mortality A:3.5%, B:2.3%, C:3.0%). Multivariate analysis showed the surgeons' experience was not associated with hospital mortality and major complications. Long-term outcomes were also compatible among three groups. CONCLUSIONS: Our standardization for TAR seemed to be an useful approach to eliminate the impact of surgeon experience on surgical outcomes if the type of surgeon was appropriately selected according to the level of operative difficulty.

Surgical outcomes of acute type A aortic dissection in patients undergoing cardiopulmonary resuscitation.

OBJECTIVES: The surgical indications for acute type A aortic dissection (AAAD) in patients in cardiopulmonary arrest remain controversial. Outcomes of AAAD for patients who underwent cardiopulmonary resuscitation (CPR) were evaluated. METHODS: Between 2004 and 2018, of the 519 patients who underwent AAAD repair, 34 (6.6%) required CPR before or on starting AAAD repair. The patients were divided into 2 groups, survivors (n = 13) and nonsurvivors (n = 21), to compare the early operative outcomes, including mortality and neurological events. RESULTS: The major cause of cardiovascular collapse requiring CPR was aortic rupture/cardiac tamponade (n = 21 [61.8%]), followed by coronary malperfusion (n = 12 [35.3%]) and acute aortic valve regurgitation (n = 3 [8.8%]). There were 3 (23.1%) patients in the survivors group and 11 (52.4%) in the nonsurvivors group who required ongoing CPR at the beginning of AAAD repair (P = .039). Of these patients, 1 survivor and 6 nonsurvivors could not achieve return of spontaneous circulation after pericardiotomy (P = .045). Although the duration from onset or arrival to the operating room was similar (P = .35 and P = .49, respectively), overall duration of CPR was shorter in survivors (10 minutes [range, 7.5-16 minutes] vs 16.5 minutes [range, 15-20 minutes]; P = .044). All survivors without any neurological deficits showed return of spontaneous circulation after pericardiotomy. Multivariate regression modeling showed that CPR duration >15 minutes was a significant risk factor for in-hospital mortality (P = .0040). CONCLUSIONS: CPR duration beyond 15 minutes may be a contraindication for AAAD repair. Moreover, we should reconsider surgery for patients who cannot achieve return of spontaneous circulation after pericardiotomy.

Efficacy of entry exclusion strategy for DeBakey type III retrograde Stanford type A acute aortic dissection.

OBJECTIVES: Resection of a primary entry tear is essential for the treatment of Stanford type A acute aortic dissection (AAAD). In DeBakey type III retrograde AAAD (DBIII-RAAAD), resection of the primary entry tear in the descending aorta is sometimes difficult. The frozen elephant trunk technique and thoracic endovascular aortic repair (TEVAR) enable the closure of the primary entry in the descending aorta. The aim of this study was to investigate the efficacy of resection or closure of primary entry, i.e. entry exclusion, in patients with DeBakey type III retrograde-AAAD. METHODS: The medical records of 654 patients with AAAD who underwent emergency surgery between January 2000 and March 2019 were retrospectively reviewed, and 80 eligible patients with DeBakey type III retrograde-AAAD were divided into the excluded (n = 50; age, 62 ± 12 years) and residual (n = 30; age, 66 ± 14 years) groups according to postoperative computed tomography angiographic data of the false lumen around the primary entry. The excluded group was defined as having a postoperative false lumen at the level of the elephant trunk or thrombosis of the endograft including primary entry. Patients with early false lumen enhancement around the elephant trunk or an unresected primary entry tear after isolated hemiarch replacement were included in the residual group. The early and long-term surgical outcomes were compared between the groups. RESULTS: The in-hospital mortality rate was 8% (6/80), with no significant difference observed between the excluded and the residual groups (10% and 7%, respectively; P > 0.99). Ninety-five percentage of the patients (20/21) achieved entry exclusion with stent grafts including the frozen elephant trunk procedure and TEVAR. Spinal cord ischaemia was not observed in either group. The cumulative overall survival at 5 years was comparable between the 2 groups (76% and 81% in the excluded and residual groups, respectively; P = 0.93). The 5-year freedom from distal aortic reoperation rate was significantly higher in the excluded group (97%) than in the residual group (97% vs 66%; P = 0.008). CONCLUSIONS: Not only resection but also closure using the entry exclusion approach for DeBakey type III retrograde-AAAD utilizing new technologies including the frozen elephant trunk technique and TEVAR might mitigate dissection-related reoperations.

Thoracic endovascular repair for retrograde acute type A aortic dissection as an alternative choice.

OBJECTIVE: The purpose of this study was to determine the clinical outcomes of thoracic endovascular aortic repair in 8 patients with acute type A aortic dissection with an entry tear in the descending aorta. SUBJECTS AND METHODS: From January 2016 to December 2018, eight patients (mean age 76 years; range 54-92 years) were treated by thoracic endovascular aortic repair due to high operative risk for conventional open repair. All patients had significant comorbidities, and two had critical organ malperfusion due to aortic dissection. Surgical outcomes were retrospectively reviewed. RESULTS: All procedures were technically successful with complete coverage of the entry tear. The proximal landing zone was Zone 1 in 2, Zone 2 in 1, Zone 3 in 4, and Zone 4 in 1 patient. Patients requiring Zone 1 and 2 thoracic endovascular aortic repair underwent aortic arch bypass simultaneously. Mean operation time was 132 min. There were no hospital deaths and no serious complications, including stroke and spinal cord ischemic injury. All patients had complete thrombosis and shrinkage of the false lumen in the ascending aorta before discharge. During up to 36-month follow-up (mean 20 ± 12 months), there were no adverse aortic events except one who died due to ischemic colitis 4 months after the procedure. CONCLUSION: Thoracic endovascular aortic repair could be a useful alternative surgical option for patients with retrograde acute type A aortic dissection with an entry in the descending aorta who are not suitable for conventional open surgery. Careful follow-up of such patients is mandatory.

Thoracic endovascular aortic repair for acute type B aortic dissection complicated by total occlusion of the abdominal aorta.

A 72-year-old man presenting with lower body malperfusion and complete paralysis was transferred for emergency treatment of a complicated acute type B aortic dissection. Enhanced computed tomography showed occlusion of the true lumen inside the abdominal aorta due to compression of the false lumen, accompanied by a Crawford extension type IV thoraco-abdominal aortic aneurysm. The primary entry tear was located at the level of the tenth thoracic vertebra above the aneurysm. Emergency thoracic endovascular aortic repair was performed to cover the entry tear and to regain perfusion of the lower body. Efforts to perform retrograde insertion of a guidewire from the femoral arteries to pass the occluded abdominal aorta were unsuccessful. A through-and-through guidewire technique between the left brachial artery and the right femoral artery was performed to deliver a Zenith TX-2 stent graft from the right femoral artery. After closure of the primary entry tear, complete recovery from the occlusion of the abdominal aorta was obtained 6 h after the onset. His paralysis recovered completely, and the postoperative course was uneventful without reperfusion injury.

Results of Surgical Repair of Hilar Renal Artery Aneurysm to Preserve Renal Blood Flow.

Objective: Surgical indications and procedures for hilar renal artery aneurysm (HRAA) are controversial in terms of invasiveness and feasibility. Catheter treatment is minimally invasive but leads to renal dysfunction due to renal infarction. This study aims to investigate the results of surgical repair of HRAA. Method: Fourteen patients (58.7±11.6 years old, 7 male) who underwent surgical repair of HRAA were retrospectively reviewed. Nine patients (64%) developed HRAA in the right renal artery, and the mean maximum aneurysmal diameter was 25.9±10.3 mm. HRAA was exposed via the extraperitoneal approach. HRAA was resected completely, and reconstruction of renal arteries was performed by direct closure in two, direct anastomosis in nine, and interposition of saphenous vein graft in three patients. Results: The average operation and renal ischemic times were 186±49 and 35±16 min, respectively. No operative death occurred, and postoperative renal function at the time of discharge had not deteriorated (creatinine, 0.74±0.15 mg/dl). During the follow-up periods (4.7±5.1 years), there was no death, no new introduction of hemodialysis, and no recurrence of renal artery aneurysm. Conclusion: Surgical repair of HRAA remains a valid option because of its operative safety, preservation of renal function, and long-term feasibility and patency.

Optimized Alkali-Metal Cationization in Secondary Ion Mass Spectrometry of Polyethylene Glycol Oligomers with up to m/z 10000: Dependence on Cation Species and Concentration.

In secondary ion mass spectrometry (SIMS), the detection of large organic molecules is accomplished using cluster ion bombardment. Ion formation often proceeds via cationization, through the attachment of (alkali) metal ions to the molecule. To study this process, the emission of secondary ions sputtered from polyethylene glycol (PEG) samples with molecular weights (MW) of 1000-10000 was examined. They were mixed with alkali-metal trifluoroacetic acid (X-TFA, where X = Li, Na, K, or Cs) in a wide range of concentrations to investigate the efficiency of cationization for 10 keV Ar2000+ cluster irradiation. Typically, cationized molecular ions [M + X]+ (with repeat units n of up to ∼250, corresponding roughly to m/z 11000) and some characteristic fragment species were observed in the mass spectra. For all alkali cations, the oligomer intensities increase strongly with the molecular composition ratios X-TFA/PEG in the samples, and values of 5-10 seem to be optimal. With increasing molecular weight, the intensity of oligomer ions relative to the total number of ions decreases; as the latter remains rather constant, this implies that more fragment species are formed. The ion yields (detected ions per primary ions) of cationized [M + Na]+ oligomers sputtered from a PEG decrease very strongly with their size n: from 5.2 × 10-6 at n = 21 (MW ∼ 1000) to 4.5 × 10-10 at n ∼ 245 (MW ∼ 11000). By contrast, the total yields Ytot+ show only a small variation for these different specimens, from 1.3 × 10-5 to 3.7 × 10-5.

Replacement of the descending thoracic aortic aneurysm with partial cardiopulmonary bypass in the era of endovascular repair.

OBJECTIVES: Although the advent of thoracic endovascular aortic repair (TEVAR) has provided an alternative treatment option for descending thoracic aortic aneurysm (DTAA), open repair still plays a crucial role in DTAA repair. The purpose of this study was to re-evaluate the operative and long-term outcomes of open repair with partial cardiopulmonary bypass, compared to the results of TEVAR with a proximal landing zone of 3 or 4. METHODS: Between 2007 and 2017, open repair was performed for 44 patients and TEVAR for 282 patients. Acute aortic dissection and open proximal anastomosis under circulatory arrest were excluded. Perioperative and long-term follow-up data were analyzed. RESULTS: In-hospital mortality rate (4.5% vs 3.2%, p = 0.42), and frequencies of spinal cord injury and neurological deficit showed no significant differences between the open repair and TEVAR groups (p = 0.41, 0.25, respectively). The propensity score-matched analysis showed similar cumulative survival (p = 0.23), but significantly higher reintervention rates for the repaired segment in the TEVAR group than in the open repair group (p = 0.0054). Twenty-two (7.8%) TEVAR patients required re-interventions for the repaired segment. Of those, 17 patients underwent additional TEVAR and 5 patients needed open conversion surgery with partial cardiopulmonary bypass. Reintervention rates for the repaired segment were significantly higher in the TEVAR group than in the open repair group (p = 0.012). CONCLUSIONS: Open repair DTAA using partial cardiopulmonary bypass showed operative outcomes comparable to TEVAR and lower reintervention rates, and thus remains an acceptable procedure for selected patients in this era of endovascular repair.

Selective Reduction Mechanism of Graphene Oxide Driven by the Photon Mode versus the Thermal Mode.

A two-dimensional nanocarbon, graphene, has attracted substantial interest due to its excellent properties. The reduction of graphene oxide (GO) has been investigated for the mass production of graphene used in practical applications. Different reduction processes produce different properties in graphene, affecting the performance of the final materials or devices. Therefore, an understanding of the mechanisms of GO reduction is important for controlling the properties of functional two-dimensional systems. Here, we determined the average structure of reduced GO prepared via heating and photoexcitation and clearly distinguished their reduction mechanisms using ultrafast time-resolved electron diffraction, time-resolved infrared vibrational spectroscopy, and time-dependent density functional theory calculations. The oxygen atoms of epoxy groups are selectively removed from the basal plane of GO by photoexcitation (photon mode), in stark contrast to the behavior observed for the thermal reduction of hydroxyl and epoxy groups (thermal mode). The difference originates from the selective excitation of epoxy bonds via an electronic transition due to their antibonding character. This work will enable the preparation of the optimum GO for the intended applications and expands the application scope of two-dimensional systems.

Type IIIB endoleak from stent suture lines of a thoracic endograft.

We report a case of a patient with type IIIB endoleak after thoracic endovascular aortic repair that remained undetected by computed tomography and was first diagnosed during open conversion surgery. The aneurysm enlarged gradually from 60 to 78 mm without type I and type II endoleaks during 3 to 6 years after thoracic endovascular aortic repair. Type IIIB endoleaks from nitinol stent suture lines were detected, and the endograft was then explanted and replaced by a vascular graft.

Surgical Outcome of Abdominal Aortic Aneurysm Replacement in Patients with Connective Tissue Disorders under 30 Years of Age.

Objectives: Abdominal aortic aneurysm (AAA) in patients <30 years old is relatively rare. We retrospectively analyzed patients <30 years who received an AAA replacement. Materials: Among 3,003 patients who received an AAA replacement during the last 40 years, 10 patients <30 years old were retrospectively reviewed. All patients suffered from a connective tissue disease: eight from Marfan syndrome and two from Loeys-Dietz syndrome. Five patients had a history of cardiovascular surgery. Aortic pathologies were a dissection type in eight patients and a non-dissection type in two. All patients received a graft replacement of infrarenal AAA, with a bifurcated graft in six patients and a straight graft in four. Results: Except for cases that were urgent and emergent, rapid aneurysm expansion was noted in all cases. Mean AAA diameter at surgery was 46.7±9.2 mm. No hospital mortality was recorded. Eight patients required 10 additional cardiovascular surgeries: two root replacements, two total arch replacements, two descending aortic replacements, and four thoracoabdominal replacements. Conclusion: AAA replacement in patients <30 years is safe. In younger patients with a connective tissue disease, AAA should be included in the routine medical check-up, and earlier surgical indication should be considered for its rapid expansion.

Surgery for a Late Type IIIb Endoleak From a Fabric Tear of an Excluder Stent Graft.

An 85-year-old male patient, who had undergone endovascular abdominal aortic aneurysm repair (EVAR) using the Gore Excluder stent graft 10 years ago, was referred for intermittent abdominal pain. He also received coil embolization of the lumbar arteries for a persistent type II endoleak, resulting in continued aneurysmal dilation at 4, 6, and 8 years after the EVAR. The maximum size of the aneurysm sac was dilated from the initial size of 49 mm × 55 mm to 78 mm × 90 mm, and the contrast medium was observed around the proximal portion of the stent graft, suggesting the presence of a type Ia or II endoleak. Because the definite cause of the dilation was unclear and adequate proximal landing zone was not available to deploy an aortic cuff, emergent laparotomy was indicated to treat this symptomatic aneurysm dilation. A type IIIb endoleak due to fabric disruption of the main body was diagnosed, and the bleeding was controlled using a fibrin sealant patch. To reinforce the hemostasis site from the inside of the stent graft, a 28 mm × 3-cm Excluder aortic cuff was deployed inside the main trunk next day. At 1-year follow-up, his condition was stable without evidence of reexpansion of the aneurysmal sac.

Endovascular repair of thrombosed-type acute Type A aortic dissection with critical renal artery malperfusion.

An 81-year-old woman was referred to our centre for emergency surgery with a suspected diagnosis of acute aortic dissection. Laboratory tests showed marked elevation of serum creatinine and blood urea nitrogen. Enhanced computed tomography (CT) demonstrated Type A aortic dissection with a thrombosed false lumen in the ascending aorta. The primary entry tear was located 2 cm distal to the left subclavian artery. Malperfusion of bilateral renal arteries was also evident due to compression by the false lumen. Considering her poor preoperative condition, thoracic endovascular repair of the entry was performed. The primary entry tear was covered using a covered Zenith TX-D stent graft, and a supplemental non-covered Zenith TX-D stent was deployed from the distal edge of the stent graft to the infrarenal aorta. After 5 days of dialysis and additional renal angioplasty for the stenotic left renal artery, her renal function recovered to normal. Her postoperative course was uneventful. Enhanced CT 1 month after surgery showed obliteration of the false lumen of the ascending aorta and patent renal arteries bilaterally.

Acute type A aortic dissection repair in younger patients.

AIM: To evaluate the surgical outcomes and midterm results of patients under 50 years old with acute type A aortic dissection (AAAD). METHODS: The study population included 51 patients who underwent AAAD repair between 2003 and 2016. Of these 51 patients, 46 (90.1%) were males and 14 (27.5%) had connective tissue disorders. Twenty-five patients (49.0%) had a body mass index >25.0 kg/m2 and two patients were pregnant. Total arch replacement was performed in 39 patients (76.5%) and hemiarch replacement in 12 patients (23.5%). Twenty patients (39.2%) underwent concomitant surgeries, including root replacement, lower limb bypass, or coronary artery bypass grafting. RESULTS: There was one in-hospital death (2.0%). Median follow-up was 55 months and overall survival rates were 87.7% at 5 years and 81.9% at 10 years. Rates of freedom from reoperation were 60.2% at 5 years and 50.2% at 10 years. Eighteen patients (35.3%) required reoperation, due to progressive aortic dilatation, new dissection in the aortic root, infection, and hemolysis. A patent false lumen represented a significant risk factor for reoperation (P < 0.001). Four patients (7.8%) underwent reoperation within 3 months after the initial repair. CONCLUSIONS: Surgical outcomes after AAAD repair for young patients were satisfactory. A patent false lumen significantly increased the need for reoperation (P = 0.002), but did not affect long-term survival. Close follow-up is mandatory after the initial repair in young patients following AAAD.

Early and late outcomes of open repair for dissecting aneurysms of the descending or thoraco-abdominal aorta.

OBJECTIVES: Although open repair is the standard surgical option for dissecting descending thoracic aneurysms (DTAs) and thoraco-abdominal aorta aneurysms (TAAAs), it remains a significant challenge with considerable perioperative morbidity and mortality. We retrospectively analysed early and late outcomes of open repair for these aortic aneurysms. METHODS: Early and late outcomes were investigated for 223 consecutive patients who underwent open repair for dissecting DTA or TAAA between January 2003 and December 2014 (mean age 55 ± 16 years). The basic strategy for open surgery comprised liberal use of deep hypothermia and aggressive preservation or reattachment of intercostal arteries, i.e. donor arteries for the artery of Adamkiewicz. RESULTS: Deep hypothermia was used in 150 (67.3%) patients. The overall in-hospital mortality rate was 3.6% and 1.5% for elective cases. The rates of spinal cord ischaemic injury and stroke were 3.1% and 4.5%, respectively. During follow-up (mean 63 ± 40 months), overall 5-year survival rates was 89.2 ± 2.4% and 91.3 ± 2.8% and 86.3 ± 4.1% for DTA and TAAA, respectively. Five- and 10-year rates of freedom from aortic events, defined as surgery for initial operation-related events or for downstream aortic dilation, were 89.1 ± 3.5% and 68.2 ± 7.8% for DTA and 100% and 96.6 ± 3.4% for TAAA, respectively (P < 0.01). CONCLUSIONS: Our approach in treating this aortic pathology showed favourable early and long-term outcomes with acceptable neurological complication rates. More careful follow-up is necessary in patients with DTA repair, because downstream aortic enlargement occurs in some patients.

Peptide Fragmentation and Surface Structural Analysis by Means of ToF-SIMS Using Large Cluster Ion Sources.

Peptide or protein structural analysis is crucial for the evaluation of biochips and biodevices, therefore an analytical technique with the ability to detect and identify protein and peptide species directly from surfaces with high lateral resolution is required. In this report, the efficacy of ToF-SIMS to analyze and identify proteins directly from surfaces is evaluated. Although the physics governing the SIMS bombardment process precludes the ability for researchers to detect intact protein or larger peptides of greater than a few thousand mass unit directly, it is possible to obtain information on the partial structures of peptides or proteins using low energy per atom argon cluster ion beams. Large cluster ion beams, such as Ar clusters and C60 ion beams, produce spectra similar to those generated by tandem MS. The SIMS bombardment process also produces peptide fragment ions not detected by conventional MS/MS techniques. In order to clarify appropriate measurement conditions for peptide structural analysis, peptide fragmentation dependency on the energy of a primary ion beam and ToF-SIMS specific fragment ions are evaluated. It was found that the energy range approximately 6 ≤ E/n ≤ 10 eV/atom is most effective for peptide analysis based on peptide fragments and [M + H] ions. We also observed the cleaving of side chain moieties at extremely low-energy E/n ≤ 4 eV/atom.

Yields and images of secondary ions from organic materials by different primary Bi ions in time-of-flight secondary ion mass spectrometry.

RATIONALE: Bi cluster ions are used as a source of primary ions for time-of-flight secondary ion mass spectrometry (TOF-SIMS), and it has been recognized that secondary ion yields of macromolecules are higher with Bi cluster ions than with monomer ions or other cluster ions such as Cs(+), Ga(+) and Aun (+). However, the analysis conditions of Bi cluster TOF-SIMS are not sufficiently established. This study provides information on the secondary ion yields, damage cross-section and spatial resolution obtained with different primary Bi ions. METHODS: We investigated the secondary ion yields, damage cross-section and spatial resolution using three different primary Bi ions in TOF-SIMS. The primary ions selected were Bi1(+), Bi3(+) and Bi3(2)(+) that were accelerated with 25 kV and the positively charged secondary ions were analyzed. The samples were 1, 2-distearoyl-sn-glycero-3-phosphocholine (C44H88NO8P, DSPC), which is a typical lipid, and N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (C44H32N2, NPD) and 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine (C66H48N4, 2-TNATA), which are organic functional materials. RESULTS: Although the secondary ion yields of DSPC were highest when measured with Bi3(+), the spatial resolution obtained from all DSPC analyses could not be evaluated because of the low intensity of the secondary molecular ions. On the other hand, for both NPD and 2-TNATA, the secondary ion yields were highest when imaged with Bi3(2)(+). Also, we obtained the highest spatial resolution using Bi3(2)(+). In the analysis of all molecules, the damage cross-section obtained with Bi3(2)(+) was also the highest. CONCLUSIONS: When secondary ions were sensitively detected, images of the high spatial resolution were obtained by using Bi3(2)(+). On the other hand, when the secondary ion sensitivity was low, the spatial resolution depended on the yields of secondary ions, implying that the selection of the primary ion species is crucial for SIMS analysis of large molecules.